Cyclic di-nucleotides as modulators of STING

ABSTRACT

A compound of formula (1) 
                         
Or a pharmaceutically acceptable salt and tautomers thereof, compositions, combinations and medicaments containing said compounds and processes for their preparation. The invention also relates to the use of said compounds, combinations, compositions and medicaments, in the treatment of diseases and conditions in which modulation of STING (Stimulator of Interferon Genes) is beneficial, for example inflammation, allergic and autoimmune diseases, infectious diseases, cancer and as vaccine adjuvants.

FIELD OF THE INVENTION

The present invention relates to compounds, compositions, combinations and medicaments containing said compounds and processes for their preparation. The invention also relates to the use of said compounds, combinations, compositions and medicaments, in the treatment of diseases and conditions in which modulation of STING (Stimulator of Interferon Genes) is beneficial, for example inflammation, allergic and autoimmune diseases, infectious diseases, cancer and as vaccine adjuvants

BACKGROUND TO THE INVENTION

Vertebrates are constantly threatened by the invasion of microorganisms and have evolved mechanisms of immune defence to eliminate infective pathogens. In mammals, this immune system comprises two branches; innate immunity and adaptive immunity. The innate immune system is the first line of defence which is initiated by Pattern Recognition Receptors (PRRs) which detect ligands from the pathogens as well as damage associated molecular patterns (Takeuchi O. et al, Cell, 2010: 140, 805-820). A growing number of these receptors have been identified including Toll-like receptors (TLRs), C-type lectin receptors, retinoic acid inducible gene I (RIG-I)-like receptors and NOD-like receptors (NLRs) and also double stranded DNA sensors. Activation of PRRs leads to up-regulation of genes involved in the inflammatory response including type 1 interferons, pro-inflammatory cytokines and chemokines which suppress pathogen replication and facilitate adaptive immunity.

The adaptor protein STING (Stimulator of Interferon Genes), also known as TMEM 173, MPYS, MITA and ERIS, has been identified as a central signalling molecule in the innate immune response to cytosolic nucleic acids (Ishikawa H and Barber G N, Nature, 2008: 455, 674-678; WO2013/1666000). Activation of STING results in up-regulation of IRF3 and NFκB pathways leading to induction of Interferon- and other cytokines. STING is critical for responses to cytosolic DNA of pathogen or host origin, and of unusual nucleic acids called Cyclic Dinucleotides (CDNs)

CDNs were first identified as bacterial secondary messengers responsible for controlling numerous responses in the prokaryotic cell. Bacterial CDNs, such as c-di-GMP are symmetrical molecules characterised by two 3′,5′ phosphodiester linkages.

Direct activation of STING by bacterial CDNs has recently been confirmed through X-ray crystallography (Burdette D L and Vance R E, Nature Immunology, 2013: 14, 19-26). Bacterial CDNs and their analogues have consequently attracted interest as potential vaccine adjuvants (Libanova R. et al, Microbial Biotechnology 2012: 5, 168-176; WO2007/054279, WO2005/087238

More recently, the response to cytosolic DNA has been elucidated and shown to involve generation, by an enzyme called cyclic GMP-AMP synthase (cGAS, previously known as C6orf150 or MB21D1), of a novel mammalian CDN signalling molecule identified as cGAMP, which then activates STING. Unlike bacterial CDNs cGAMP is an unsymmetrical molecule characterised by it's mixed 2′,5′ and 3′,5′ phosphodiester linkages. (Gao P et al, Cell, 2013: 153, 1-14). Interaction of cGAMP (II) with STING has also been demonstrated by X-ray crystallography (CaiX et al, Molecular Cell, 2014: 54, 289-296).

Interferon was first described as a substance which could protect cells from viral infection (Isaacs & Lindemann, J. Virus Interference. Proc. R. Soc. Lon. Ser. B. Biol. Sci. 1957: 147, 258-267). In man, the type I interferons are a family of related proteins encoded by genes on chromosome 9 and encoding at least 13 isoforms of interferon alpha (IFNα) and one isoform of interferon beta (IFNβ). Recombinant IFNα was the first approved biological therapeutic and has become an important therapy in viral infections and in cancer. As well as direct antiviral activity on cells, interferons are known to be potent modulators of the immune response, acting on cells of the immune system.

Administration of a small molecule compound which could stimulate the innate immune response, including the activation of type I interferons and other cytokines, could become an important strategy for the treatment or prevention of human diseases including viral infections. This type of immunomodulatory strategy has the potential to identify compounds which may be useful not only in infectious diseases but also in cancer (Krieg. Curr. Oncol. Rep., 2004: 6(2), 88-95), allergic diseases (Moisan J. et al, Am. J. Physiol. Lung Cell Mol. Physiol., 2006: 290, L987-995), other inflammatory conditions such as irritable bowel disease (Rakoff-Nahoum S., Cell., 2004, 23, 118(2): 229-41), and as vaccine adjuvants (Persing et al. Trends Microbiol. 2002: 10(10 Suppl), 532-7).

Allergic diseases are associated with a Th2-biased immune-response to allergens. Th2 responses are associated with raised levels of IgE, which, via its effects on mast cells, promotes a hypersensitivity to allergens, resulting in the symptoms seen, for example, in allergic rhinitis and asthma. In healthy individuals the immune-response to allergens is more balanced with a mixed Th2/Th1 and regulatory T cell response. Induction of Type 1 interferons have been shown to result in reduction of Th2-type cytokines in the local environment and promote Th1/Treg responses. In this context, induction of type 1 interferons by, for example, activation of STING, may offer benefit in treatment of allergic diseases such as asthma and allergic rhinitis (Huber J. P. et al J Immunol 2010: 185, 813-817)

Certain compounds of the invention have been shown to bind to STING and to induce type 1 interferons and other cytokines on incubation with human PBMCs) Compounds which induce human interferons may be useful in the treatment of various disorders, for example the treatment of allergic diseases and other inflammatory conditions for example allergic rhinitis and asthma, the treatment of infectious diseases and cancer, and may also be useful as vaccine adjuvants. Certain compounds of the invention may bind to STING but act as antagonists and these could be useful in the treatment, for example of autoimmune diseases.

Certain compounds of the invention may be potent immunomodulators and accordingly, care should be exercised in their handling.

It is envisaged that targeting STING with activation or inhibiting agents may be a promising approach for treating diseases and conditions in which modulation for the type 1 IFN pathway is beneficial, including inflammatory, allergic and autoimmune diseases, infectious diseases, cancer and as vaccine adjuvants.

SUMMARY OF THE INVENTION

In one aspect there is provided a compound of formula (I)

wherein

Y¹ and Y² are independently CH₂ or 0;

R₁ is OH and R₂ is NH₂ or R is NH₂ and R² is H;

R₃ is OH and R₄ is NH₂ or R₃ is NH₂ and R⁴ is H;

R₅═OH, F;

R═OH, F;

and when both R₅ and R₆ are OH, at least one of Y₁ and Y₂ is CH₂

(including tautomers thereof) or a pharmaceutically acceptable salt thereof.

In a further aspect of the present invention, there is provided a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and one or more of pharmaceutically acceptable excipients.

In a further aspect of the present invention, there is provided a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in therapy.

In a further aspect of the present invention, there is provided a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in the treatment of a disease or condition in which modulation STING is beneficial.

In a further aspect of the present invention, there is provided a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in the treatment of inflammation, allergic and autoimmune diseases, infectious diseases, cancer and as vaccine adjuvants

In a further aspect of the present invention, there is provided a method of the treatment of a disease or condition in which modulation STING is beneficial. In a subject comprising administering a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect of the present invention, there is provided a method of the treatment inflammation, allergic and autoimmune diseases, infectious diseases and cancer in a subject comprising administering a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect of the present invention, there is provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for use the treatment of a disease or condition in which modulation of STING is beneficial.

In a further aspect of the present invention, there is provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for use the treatment of inflammation, allergic and autoimmune diseases, infectious diseases and cancer.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent.

In a further aspect of the present invention, there is provided a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent and one or more of pharmaceutically acceptable excipients.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent for use in therapy.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent for use in the treatment of a disease or condition in which modulation of STING is beneficial.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent for use in the treatment of inflammation, allergic and autoimmune diseases, infectious diseases and cancer

In a further aspect of the present invention, there is provided a method of the treatment of a disease or condition in which modulation of STING is beneficial. In a subject comprising administering a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent

In a further aspect of the present invention, there is provided a method of the treatment of inflammation, allergic and autoimmune diseases, infectious diseases and cancer in a subject comprising administering a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent

In a further aspect there is further provided a vaccine adjuvant comprising a compound of formula (I), or a pharmaceutically acceptable salt thereof.

In a further aspect there is further provided an immunogenic composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

In a further aspect there is further provided an immunogenic composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in the treatment or prevention of disease.

In a further aspect there is further provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of an immunogenic composition comprising an antigen or antigen composition, for the treatment or prevention of disease.

In a further aspect there is further provided a method of treating or preventing disease comprising the administration to a human subject suffering from or susceptible to disease, an immunogenic composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

In a further aspect there is further provided a vaccine composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in the treatment or prevention of disease.

In a further aspect there is further provided a vaccine composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in the treatment or prevention of disease

In a further aspect there is further provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of a vaccine composition comprising an antigen or antigen composition, for the treatment or prevention of disease.

In a further aspect there is further provided a method of treating or preventing disease comprising the administration to a human subject suffering from or susceptible to disease, a vaccine composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, “a compound of the invention” includes all solvates, complexes, polymorphs, radiolabelled derivatives, tautomers, stereoisomers and optical isomers of the compounds of formula (I) and salts thereof.

As used herein, the term “effective amount” means that amount of a drug or pharmaceutical agent that will elicit the biological or medical response of a tissue, system, animal or human that is being sought, for instance, by a researcher or clinician. Furthermore, the term “therapeutically effective amount” means any amount which, as compared to a corresponding subject who has not received such amount, results in improved treatment, healing, prevention, or amelioration of a disease, disorder, or side effect, or a decrease in the rate of advancement of a disease or disorder. The term also includes within its scope amounts effective to enhance normal physiological function.

The term “prophylaxis” includes prevention and refers to a measure or procedure which is to prevent rather than cure or treat a disease. Preventing refers to a reduction in risk of acquiring or developing a disease causing at least one clinical symptom of the disease not to develop in a subject that may be exposed to a disease causing agent or a subject predisposed to the disease in advance of disease outset.

As used herein, the term “pharmaceutically acceptable” refers to those compounds, materials, compositions, and dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

As used herein, “pharmaceutically acceptable excipients includes all diluents, carriers binders, glidants and other components of pharmaceutical formulations with which the compound of the invention is administered.

The compounds of the invention may exist in solid or liquid form. In solid form, compound of the invention may exist in a continuum of solid states ranging from fully amorphous to fully crystalline. The term ‘amorphous’ refers to a state in which the material lacks long range order at the molecular level and, depending upon the temperature, may exhibit the physical properties of a solid or a liquid. Typically such materials do not give distinctive X-ray diffraction patterns and, while exhibiting the properties of a solid, are more formally described as a liquid. Upon heating, a change from solid to liquid properties occurs which is characterized by a change of state, typically second order (‘glass transition’). The term ‘crystalline’ refers to a solid phase in which the material has a regular ordered internal structure at the molecular level and gives a distinctive X-ray diffraction pattern with defined peaks. Such materials when heated sufficiently will also exhibit the properties of a liquid, but the change from solid to liquid is characterized by a phase change, typically first order (‘melting point’).

The compounds of the invention may have the ability to crystallize in more than one form, a characteristic, which is known as polymorphism, and it is understood that such polymorphic forms (“polymorphs”) are within the scope of the invention. Polymorphism generally can occur as a response to changes in temperature or pressure or both and can also result from variations in the crystallization process. Polymorphs can be distinguished by various physical characteristics known in the art such as x-ray diffraction patterns, solubility and melting point.

The compound of formula (I) may exist in solvated and unsolvated forms. As used herein, the term “solvate” refers to a complex of variable stoichiometry formed by a solute (in this invention, a compound of formula (I) or a salt) and a solvent. Such solvents for the purpose of the invention may not interfere with the biological activity of the solute. The skilled artisan will appreciate that pharmaceutically acceptable solvates may be formed for crystalline compounds wherein solvent molecules are incorporated into the crystalline lattice during crystallization. The incorporated solvent molecules may be water molecules or non-aqueous such as ethanol, isopropanol, DMSO, acetic acid, ethanolamine, and ethyl acetate molecules. Crystalline lattice incorporated with water molecules are typically referred to as “hydrates”. Hydrates include stoichiometric hydrates as well as compositions containing variable amounts of water. The present invention includes all such solvates.

It is also noted that the compounds of formula (I) may form tautomers. ‘Tautomers’ refer to compounds that are interchangeable forms of a particular compound structure, and that vary in the displacement of hydrogen atoms and electrons. Thus, two structures may be in equilibrium through the movement of t electrons and an atom (usually H). For example, enols and ketones are tautomers because they are rapidly interconverted by treatment with either acid or base. It is understood that all tautomers and mixtures of tautomers of the compounds of the present invention are included within the scope of the compounds of the present invention. For absolute clarity, in the compounds of formula (I) when R¹ or R³ represent OH, the compounds will form the keto tautomer (═O).

In one aspect of the present invention, at least one of Y₁ and Y₂ is CH₂.

In one aspect of the present invention, Y¹ is CH and Y² is O.

In one aspect of the present invention Y¹ is O and Y² is CH

In one aspect of the present invention, Y¹ and Y² are both CH.

In one aspect of the present invention Y¹ and Y² are both O and at least one of R₅ and R₆ is F.

In one aspect of the present invention, R³ is NH₂ and R⁴ is H

In one aspect of the present invention R² is NH₂ and R¹ is OH

In one aspect of the present invention, R³ is NH₂, R⁴ is H, R² is NH₂ and R¹ is OH.

In one aspect of the present invention, R³ is NH₂, R⁴ is H, R² is NH₂, R¹ is OH, R⁵ is OH and R⁶ is OH.

While aspects for each variable have generally been listed above separately for each variable this invention includes those compounds in which several or each aspect in formula (I) is selected from each of the aspects listed above. Therefore, this invention is intended to include all combinations of aspects for each variable.

Examples of compounds of the prevent invention include the following:

-   (1S,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione -   (1R,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione -   (1S,6R,8R,9R,10S,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione -   (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9-fluoro-3,12,18-trihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione

The compounds of Formula (I) may be in the form of a salt.

Typically, the salts of the present invention are pharmaceutically acceptable salts. Salts encompassed within the term “pharmaceutically acceptable salts” refer to non-toxic salts of the compounds of this invention. For a review on suitable salts see Berge et al, J. Pharm. Sci. 1977, 66, 1-19.

Suitable pharmaceutically acceptable salts can include acid addition salts.

A pharmaceutically acceptable acid addition salt can be formed by reaction of a compound of formula (I) with a suitable inorganic or organic acid (such as hydrobromic, hydrochloric, sulfuric, nitric, phosphoric, p-toluenesulfonic, benzenesulfonic, methanesulfonic, ethanesulfonic, naphthalenesulfonic such as 2-naphthalenesulfonic), optionally in a suitable solvent such as an organic solvent, to give the salt which is usually isolated for example by crystallisation and filtration. A pharmaceutically acceptable acid addition salt of a compound of formula (I) can comprise or be for example a hydrobromide, hydrochloride, sulfate, nitrate, phosphate, p-toluenesulfonate, benzenesulfonate, methanesulfonate, ethanesulfonate, naphthalenesulfonate (e.g. 2-naphthalenesulfonate) salt.

Other non-pharmaceutically acceptable salts, e.g. trifluoroacetates, may be used, for example in the isolation of compounds of the invention, and are included within the scope of this invention.

The invention includes within its scope all possible stoichiometric and non-stoichiometric forms of the compounds of formula (I).

While it is possible that, for use in therapy, the compound of the invention may be administered as the raw chemical, it is possible to present the compound of the invention as the active ingredient as a pharmaceutical composition. Such compositions can be prepared in a manner well known in the pharmaceutical art and comprise at least one active compound. Accordingly, the invention further provides pharmaceutical compositions comprising a compound of the invention and one or more pharmaceutically acceptable excipients. The excipient(s) must be acceptable in the sense of being compatible with the other ingredients of the composition and not deleterious to the recipient thereof. In accordance with another aspect of the invention there is also provided a process for the preparation of a pharmaceutical composition including the agent, or pharmaceutically acceptable salts thereof, with one or more pharmaceutically acceptable excipients. The pharmaceutical composition can be for use in the treatment and/or prophylaxis of any of the conditions described herein.

Generally, the compound of the invention is administered in a pharmaceutically effective amount. The amount of the compound actually administered will typically be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound-administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like.

Pharmaceutical compositions may be presented in unit dose forms containing a predetermined amount of active ingredient per unit dose. The term “unit dosage forms” refers to physically discrete units suitable as unitary dosages for human subjects and other mammals, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect, in association with a suitable pharmaceutical excipient, vehicle or carrier. Typical unit dosage forms include prefilled, premeasured ampules or syringes of the liquid compositions or pills, tablets, capsules or the like in the case of solid compositions.

Preferred unit dosage compositions are those containing a daily dose or sub-dose, or an appropriate fraction thereof, of an active ingredient. Such unit doses may therefore be administered once or more than once a day. Such pharmaceutical compositions may be prepared by any of the methods well known in the pharmacy art.

Pharmaceutical compositions may be adapted for administration by any appropriate route, for example by the oral (including buccal or sublingual), rectal, inhaled, intranasal, topical (including buccal, sublingual or transdermal), vaginal or parenteral (including subcutaneous, intramuscular, intravenous or intradermal) route. Such compositions may be prepared by any method known in the art of pharmacy, for example by bringing into association the active ingredient with the carrier(s) or excipient(s).

Pharmaceutical compositions adapted for oral administration may be presented as discrete units such as capsules or tablets; powders or granules; solutions or suspensions in aqueous or non-aqueous liquids; edible foams or whips; or oil-in-water liquid emulsions or water-in-oil liquid emulsions.

For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert excipient such as ethanol, glycerol, water and the like. Powders are prepared by reducing the compound to a suitable fine size and mixing with a similarly prepared pharmaceutical excipient such as an edible carbohydrate, as, for example, starch or mannitol. Flavouring, preservative, dispersing and colouring agent can also be present.

Capsules are made by preparing a powder mixture, as described above, and filling formed gelatin sheaths. Excipients including glidants and lubricants such as colloidal silica, talc, magnesium stearate, calcium stearate or solid polyethylene glycol can be added to the powder mixture before the filling operation. A disintegrating or solubilizing agent such as agar-agar, calcium carbonate or sodium carbonate can also be added to improve the availability of the medicament when the capsule is ingested.

Moreover, when desired or necessary, excipients including suitable binders, glidants, lubricants, sweetening agents, flavours, disintegrating agents and colouring agents can also be incorporated into the mixture. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like. Tablets are formulated, for example, by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant and pressing into tablets. A powder mixture is prepared by mixing the compound, suitably comminuted, with a diluent or base as described above, and optionally, with a binder such as carboxymethylcellulose, an aliginate, gelatin, or polyvinyl pyrrolidone, a solution retardant such as paraffin, a resorption accelerator such as a quaternary salt and/or an absorption agent such as bentonite, kaolin or dicalcium phosphate. The powder mixture can be granulated by wetting with a binder such as syrup, starch paste, acadia mucilage or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the result is imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. The compounds of the present invention can also be combined with a free flowing inert carrier and compressed into tablets directly without going through the granulating or slugging steps. A clear or opaque protective coating consisting of a sealing coat of shellac, a coating of sugar or polymeric material and a polish coating of wax can be provided. Dyestuffs can be added to these coatings to distinguish different unit dosages.

Oral fluids such as solution, suspensions, syrups and elixirs can be prepared in dosage unit form so that a given quantity contains a predetermined amount of the compound. Syrups can be prepared by dissolving the compound in a suitably flavoured aqueous solution, while elixirs are prepared through the use of a non-toxic alcoholic vehicle. Suspensions can be formulated by dispersing the compound in a non-toxic vehicle. Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols and polyoxy ethylene sorbitol ethers, preservatives, flavor additive such as peppermint oil or natural sweeteners or saccharin or other artificial sweeteners, and the like can also be added.

Where appropriate, dosage unit compositions for oral administration can be microencapsulated. The composition can also be prepared to prolong or sustain the release as for example by coating or embedding particulate material in polymers, wax or the like.

The compounds of the invention may also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine or phosphatidylcholines.

Pharmaceutical compositions adapted for transdermal administration may be presented as discrete patches intended to remain in intimate contact with the epidermis of the recipient for a prolonged period of time.

Pharmaceutical compositions adapted for topical administration may be formulated as ointments, creams, suspensions, lotions, powders, solutions, pastes, gels, sprays, aerosols or oils.

For treatments of the eye or other external tissues, for example mouth and skin, the compositions are preferably applied as a topical ointment or cream. When formulated in an ointment, the active ingredient may be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active ingredient may be formulated in a cream with an oil-in-water cream base or a water-in-oil base.

Pharmaceutical compositions adapted for topical administrations to the eye include eye drops wherein the active ingredient is dissolved or suspended in a suitable carrier, especially an aqueous solvent.

Pharmaceutical compositions adapted for topical administration in the mouth include lozenges, pastilles and mouth washes.

Pharmaceutical compositions adapted for rectal administration may be presented as suppositories or as enemas.

Dosage forms for nasal or inhaled administration may conveniently be formulated as aerosols, solutions, suspensions drops, gels or dry powders.

Compositions for intranasal administration include aqueous compositions administered to the nose by drops or by pressurised pump. Suitable compositions contain water as the diluent or carrier for this purpose. Compositions for administration to the lung or nose may contain one or more excipients, for example one or more suspending agents, one or more preservatives, one or more surfactants, one or more tonicity adjusting agents, one or more co-solvents, and may include components to control the pH of the composition, for example a buffer system. Further, the compositions may contain other excipients such as antioxidants, for example sodium metabisulphite, and taste-masking agents. Compositions may also be administered to the nose or other regions of the respiratory tract by nebulisation.

Intranasal compositions may permit the compound(s) of formula (I) or (a) pharmaceutically acceptable salt(s) thereof to be delivered to all areas of the nasal cavities (the target tissue) and further, may permit the compound(s) of formula (I) or (a) pharmaceutically acceptable salt(s) thereof to remain in contact with the target tissue for longer periods of time. A suitable dosing regime for intranasal compositions would be for the patient to inhale slowly through the nose subsequent to the nasal cavity being cleared. During inhalation the composition would be administered to one nostril while the other is manually compressed. This procedure would then be repeated for the other nostril. Typically, one or two sprays per nostril would be administered by the above procedure one, two, or three times each day, ideally once daily. Of particular interest are intranasal compositions suitable for once-daily administration.

The suspending agent(s), if included, will typically be present in an amount of from 0.1 to 5% (w/w), such as from 1.5% to 2.4% (w/w), based on the total weight of the composition. Examples of pharmaceutically acceptable suspending agents include, but are not limited to, Avicel® (microcrystalline cellulose and carboxymethylcellulose sodium), carboxymethylcellulose sodium, veegum, tragacanth, bentonite, methylcellulose, xanthan gum, carbopol and polyethylene glycols.

Compositions for administration to the lung or nose may contain one or more excipients may be protected from microbial or fungal contamination and growth by inclusion of one or more preservatives. Examples of pharmaceutically acceptable anti-microbial agents or preservatives include, but are not limited to, quaternary ammonium compounds (for example benzalkonium chloride, benzethonium chloride, cetrimide, cetylpyridinium chloride, lauralkonium chloride and myristyl picolinium chloride), mercurial agents (for example phenylmercuric nitrate, phenylmercuric acetate and thimerosal), alcoholic agents (for example chlorobutanol, phenylethyl alcohol and benzyl alcohol), antibacterial esters (for example esters of para-hydroxybenzoic acid), chelating agents such as disodium edetate (EDTA) and other anti-microbial agents such as chlorhexidine, chlorocresol, sorbic acid and its salts (such as potassium sorbate) and polymyxin. Examples of pharmaceutically acceptable anti-fungal agents or preservatives include, but are not limited to, sodium benzoate, sorbic acid, sodium propionate, methylparaben, ethylparaben, propylparaben and butylparaben. The preservative(s), if included, may be present in an amount of from 0.001 to 1% (w/w), such as from 0.015% to 0.5% (w/w) based on the total weight of the composition.

Compositions (for example wherein at least one compound is in suspension) may include one or more surfactants which functions to facilitate dissolution of the medicament particles in the aqueous phase of the composition. For example, the amount of surfactant used is an amount which will not cause foaming during mixing. Examples of pharmaceutically acceptable surfactants include fatty alcohols, esters and ethers, such as polyoxyethylene (20) sorbitan monooleate (Polysorbate 80), macrogol ethers, and poloxamers. The surfactant may be present in an amount of between about 0.01 to 10% (w/w), such as from 0.01 to 0.75% (w/w), for example about 0.5% (w/w), based on the total weight of the composition.

One or more tonicity-adjusting agent(s) may be included to achieve tonicity with body fluids e.g. fluids of the nasal cavity, resulting in reduced levels of irritancy. Examples of pharmaceutically acceptable tonicity-adjusting agents include, but are not limited to, sodium chloride, dextrose, xylitol, calcium chloride, glucose, glycerine and sorbitol. A tonicity-adjusting agent, if present, may be included in an amount of from 0.1 to 10% (w/w), such as from 4.5 to 5.5% (w/w), for example about 5.0% (w/w), based on the total weight of the composition.

The compositions of the invention may be buffered by the addition of suitable buffering agents such as sodium citrate, citric acid, trometamol, phosphates such as disodium phosphate (for example the dodecahydrate, heptahydrate, dihydrate and anhydrous forms), or sodium phosphate and mixtures thereof.

A buffering agent, if present, may be included in an amount of from 0.1 to 5% (w/w), for example 1 to 3% (w/w) based on the total weight of the composition.

Examples of taste-masking agents include sucralose, sucrose, saccharin or a salt thereof, fructose, dextrose, glycerol, corn syrup, aspartame, acesulfame-K, xylitol, sorbitol, erythritol, ammonium glycyrrhizinate, thaumatin, neotame, mannitol, menthol, eucalyptus oil, camphor, a natural flavouring agent, an artificial flavouring agent, and combinations thereof.

One or more co-solvent(s) may be included to aid solubility of the medicament compound(s) and/or other excipients. Examples of pharmaceutically acceptable co-solvents include, but are not limited to, propylene glycol, dipropylene glycol, ethylene glycol, glycerol, ethanol, polyethylene glycols (for example PEG300 or PEG400), and methanol. In one embodiment, the co-solvent is propylene glycol.

Co-solvent(s), if present, may be included in an amount of from 0.05 to 30% (w/w), such as from 1 to 25% (w/w), for example from 1 to 10% (w/w) based on the total weight of the composition.

Compositions for inhaled administration include aqueous, organic or aqueous/organic mixtures, dry powder or crystalline compositions administered to the respiratory tract by pressurised pump or inhaler, for example, reservoir dry powder inhalers, unit-dose dry powder inhalers, pre-metered multi-dose dry powder inhalers, nasal inhalers or pressurised aerosol inhalers, nebulisers or insufflators. Suitable compositions contain water as the diluent or carrier for this purpose and may be provided with conventional excipients such as buffering agents, tonicity modifying agents and the like. Aqueous compositions may also be administered to the nose and other regions of the respiratory tract by nebulisation. Such compositions may be aqueous solutions or suspensions or aerosols delivered from pressurised packs, such as a metered dose inhaler, with the use of a suitable liquefied propellant.

Compositions for administration topically to the nose (for example, for the treatment of rhinitis) or to the lung, include pressurised aerosol compositions and aqueous compositions delivered to the nasal cavities by pressurised pump. Compositions which are non-pressurised and are suitable for administration topically to the nasal cavity are of particular interest. Suitable compositions contain water as the diluent or carrier for this purpose. Aqueous compositions for administration to the lung or nose may be provided with conventional excipients such as buffering agents, tonicity-modifying agents and the like. Aqueous compositions may also be administered to the nose by nebulisation.

A fluid dispenser may typically be used to deliver a fluid composition to the nasal cavities. The fluid composition may be aqueous or non-aqueous, but typically aqueous. Such a fluid dispenser may have a dispensing nozzle or dispensing orifice through which a metered dose of the fluid composition is dispensed upon the application of a user-applied force to a pump mechanism of the fluid dispenser. Such fluid dispensers are generally provided with a reservoir of multiple metered doses of the fluid composition, the doses being dispensable upon sequential pump actuations. The dispensing nozzle or orifice may be configured for insertion into the nostrils of the user for spray dispensing of the fluid composition into the nasal cavity. A fluid dispenser of the aforementioned type is described and illustrated in International Patent Application publication number WO 2005/044354 (Glaxo Group Limited). The dispenser has a housing which houses a fluid-discharge device having a compression pump mounted on a container for containing a fluid composition. The housing has at least one finger-operable side lever which is movable inwardly with respect to the housing to move the container upwardly in the housing by means of a cam to cause the pump to compress and pump a metered dose of the composition out of a pump stem through a nasal nozzle of the housing. In one embodiment, the fluid dispenser is of the general type illustrated in FIGS. 30-40 of WO 2005/044354.

Aqueous compositions containing a compound of formula (I) or a pharmaceutically acceptable salt thereof may also be delivered by a pump as disclosed in International Patent Application publication number WO2007/138084 (Glaxo Group Limited), for example as disclosed with reference to FIGS. 22-46 thereof, or as disclosed in United Kingdom patent application number GB0723418.0 (Glaxo Group Limited), for example as disclosed with reference to FIGS. 7-32 thereof. The pump may be actuated by an actuator as disclosed in FIGS. 1-6 of GB0723418.0.

Dry powder compositions for topical delivery to the lung by inhalation may, for example, be presented in capsules and cartridges of for example gelatine, or blisters of for example laminated aluminium foil, for use in an inhaler or insufflator. Powder blend compositions generally contain a powder mix for inhalation of the compound of formula (I) or a pharmaceutically acceptable salt thereof and a suitable powder base (carrier/diluent/excipient substance) such as mono-, di-, or polysaccharides (for example lactose or starch). Dry powder compositions may also include, in addition to the drug and carrier, a further excipient (for example a ternary agent such as a sugar ester for example cellobiose octaacetate, calcium stearate, or magnesium stearate.

In one embodiment, a composition suitable for inhaled administration may be incorporated into a plurality of sealed dose containers provided on medicament pack(s) mounted inside a suitable inhalation device. The containers may be rupturable, peelable, or otherwise openable one-at-a-time and the doses of the dry powder composition administered by inhalation on a mouthpiece of the inhalation device, as known in the art. The medicament pack may take a number of different forms, for instance a disk-shape or an elongate strip.

Representative inhalation devices are the DISKHALER™ and DISKUS™ devices, marketed by GlaxoSmithKline.

A dry powder inhalable composition may also be provided as a bulk reservoir in an inhalation device, the device then being provided with a metering mechanism for metering a dose of the composition from the reservoir to an inhalation channel where the metered dose is able to be inhaled by a patient inhaling at a mouthpiece of the device. Exemplary marketed devices of this type are TURBUHALER™ (AstraZeneca), TWISTHALER™ (Schering) and CLICKHALER™ (Innovata.)

A further delivery method for a dry powder inhalable composition is for metered doses of the composition to be provided in capsules (one dose per capsule) which are then loaded into an inhalation device, typically by the patient on demand. The device has means to rupture, pierce or otherwise open the capsule so that the dose is able to be entrained into the patient's lung when they inhale at the device mouthpiece. As marketed examples of such devices there may be mentioned ROTAHALER™ (GlaxoSmithKline) and HANDIHALER™ (Boehringer Ingelheim.)

Pressurised aerosol compositions suitable for inhalation can be either a suspension or a solution and may contain a compound of formula (I) or a pharmaceutically acceptable salt thereof and a suitable propellant such as a fluorocarbon or hydrogen-containing chlorofluorocarbon or mixtures thereof, particularly hydrofluoroalkanes, especially 1,1,1,2-tetrafluoroethane, 1,1,1,2,3,3,3-heptafluoro-n-propane or a mixture thereof. The aerosol composition may optionally contain additional composition excipients well known in the art such as surfactants e.g. oleic acid, lecithin or an oligolactic acid or derivative thereof e.g. as described in WO 94/21229 and WO 98/34596 (Minnesota Mining and Manufacturing Company) and co-solvents e.g. ethanol. Pressurised compositions will generally be retained in a canister (e.g. an aluminium canister) closed with a valve (e.g. a metering valve) and fitted into an actuator provided with a mouthpiece.

Pharmaceutical compositions adapted for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations.

Pharmaceutical compositions adapted for parental administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the composition isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The compositions may be presented in unit-dose or multi-dose containers, for example sealed ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets.

It should be understood that in addition to the ingredients particularly mentioned above, the compositions may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavouring agents.

Antisense or RNA interference molecules may be administered to the mammal in need thereof. Alternatively, constructs including the same may be administered. Such molecules and constructs can be used to interfere with the expression of the protein of interest, e.g., histone demethylase and as such, modify histone demethylation. Typically delivery is by means known in the art.

Antisense or RNA interference molecules can be delivered in vitro to cells or in vivo, e.g., to tumors of a mammal. Nodes of delivery can be used without limitations, including: intravenous, intramuscular, intraperitoncal, intra-arterial, local delivery during surgery, endoscopic, subcutaneous, and per os. Vectors can be selected for desirable properties for any particular application. Vectors can be viral or plasmid. Adenoviral vectors are useful in this regard. Tissue-specific, cell-type specific, or otherwise regulatable promoters can be used to control the transcription of the inhibitory polynucleotide molecules. Non-viral carriers such as liposomes or nanospheres can also be used.

The compounds of formula (I) and pharmaceutically acceptable salts thereof may also be formulated with vaccines as adjuvants to modulate their activity. Such compositions may contain antibody(ies) or antibody fragment(s) or an antigenic component including but not limited to protein, DNA, live or dead bacteria and/or viruses or virus-like particles, together with one or more components with adjuvant activity including but not limited to aluminium salts, oil and water emulsions, heat shock proteins, lipid A preparations and derivatives, glycolipids, other TLR agonists such as CpG DNA or similar agents, cytokines such as GM-CSF or IL-12 or similar agents.

A therapeutically effective amount of the agent will depend upon a number of factors including, for example, the age and weight of the subject, the precise condition requiring treatment and its severity, the nature of the formulation, and the route of administration, and will ultimately be at the discretion of the attendant physician or veterinarian. In particular, the subject to be treated is a mammal, particularly a human.

The agent may be administered in a daily dose. This amount may be given in a single dose per day or more usually in a number (such as two, three, four, five or six) of sub-doses per day such that the total daily dose is the same.

Suitably, the amount of the compound of the invention administered according to the present invention will be an amount selected from 0.01 mg to 1 g per day (calculated as the free or unsalted compound).

The compounds of formula (I) and pharmaceutically acceptable salts thereof may be employed alone or in combination with other therapeutic agents. The compounds of formula (I) and pharmaceutically acceptable salts thereof and the other pharmaceutically active agent(s) may be administered together or separately and, when administered separately, administration may occur simultaneously or sequentially, in any order. by any convenient route in separate or combined pharmaceutical compositions.

The amounts of the compound(s) of formula (I) or pharmaceutically acceptable salt(s) thereof and the other pharmaceutically active agent(s) and the relative timings of administration will be selected in order to achieve the desired combined therapeutic effect. The compounds of the present invention and further therapeutic agent(s) may be employed in combination by administration simultaneously in a unitary pharmaceutical composition including both compounds. Alternatively, the combination may be administered separately in separate pharmaceutical compositions, each including one of the compounds in a sequential manner wherein, for example, the compound of the invention is administered first and the other second and visa versa. Such sequential administration may be close in time (e.g. simultaneously) or remote in time. Furthermore, it does not matter if the compounds are administered in the same dosage form, e.g. one compound may be administered topically and the other compound may be administered orally. Suitably, both compounds are administered orally.

The combinations may be presented as a combination kit. By the term “combination kit” “or kit of parts” as used herein is meant the pharmaceutical composition or compositions that are used to administer the combination according to the invention. When both compounds are administered simultaneously, the combination kit can contain both compounds in a single pharmaceutical composition, such as a tablet, or in separate pharmaceutical compositions. When the compounds are not administered simultaneously, the combination kit will contain each compound in separate pharmaceutical compositions either in a single package or in separate pharmaceutical compositions in separate packages.

The combination kit can also be provided by instruction, such as dosage and administration instructions. Such dosage and administration instructions can be of the kind that are provided to a doctor, for example by a drug product label, or they can be of the kind that are provided by a doctor, such as instructions to a patient.

When the combination is administered separately in a sequential manner wherein one is administered first and the other second or vice versa, such sequential administration may be close in time or remote in time. For example, administration of the other agent several minutes to several dozen minutes after the administration of the first agent, and administration of the other agent several hours to several days after the administration of the first agent are included, wherein the lapse of time is not limited. For example, one agent may be administered once a day, and the other agent may be administered 2 or 3 times a day, or one agent may be administered once a week, and the other agent may be administered once a day and the like.

It will be clear to a person skilled in the art that, where appropriate, the other therapeutic ingredients(s) may be used in the form of salts, for example as alkali metal or amine salts or as acid addition salts, or prodrugs, or as esters, for example lower alkyl esters, or as solvates, for example hydrates, to optimise the activity and/or stability and/or physical characteristics, such as solubility, of the therapeutic ingredient. It will be clear also that, where appropriate, the therapeutic ingredients may be used in optically pure form.

When combined in the same composition it will be appreciated that the two compounds must be stable and compatible with each other and the other components of the composition and may be formulated for administration. When formulated separately they may be provided in any convenient composition, conveniently, in such a manner as known for such compounds in the art.

When the compound of formula (I) is used in combination with a second therapeutic agent active against the same disease, condition or disorder, the dose of each compound may differ from that when the compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.

In one embodiment the mammal in the methods and uses of the present invention is a human.

The compounds of the invention are useful in the treatment of diseases and conditions in which modulation of STING is beneficial. This includes inflammation, allergic and autoimmune diseases, infectious diseases and cancer.

As modulators of the immune response the compounds of formula (I) and pharmaceutically acceptable salts thereof may also be useful, as stand-alone or in combination as an adjuvants in the treatment of diseases and conditions in which modulation of STING is beneficial

In one aspect, the disease or condition is inflammation, allergy and autoimmune disorders

Autoimmune diseases associated include, but are not limited to systemic lupus erythmatosus, Psoriasis, insulin-dependent diabetes mellitus (IDDM), dermatomyositis and Sjogren's syndrome (SS).

Inflammation represents a group of vascular, cellular and neurological responses to trauma. Inflammation can be characterised as the movement of inflammatory cells such as monocytes, neutrophils and granulocytes into the tissues. This is usually associated with reduced endothelial barrier function and oedema into the tissues. Inflammation can be classified as either acute or chronic. Acute inflammation is the initial response of the body to harmful stimuli and is achieved by the increased movement of plasma and leukocytes from the blood into the injured tissues. A cascade of biochemical event propagates and matures the inflammatory response, involving the local vascular system, the immune system, and various cells within the injured tissue. Prolonged inflammation, known as chronic inflammation, leads to a progressive shift in the type of cells which are present at the site of inflammation and is characterised by simultaneous destruction and healing of the tissue from the inflammatory process.

When occurring as part of an immune response to infection or as an acute response to trauma, inflammation can be beneficial and is normally self-limiting. However, inflammation can be detrimental under various conditions. This includes the production of excessive inflammation in response to infectious agents, which can lead to significant organ damage and death (for example, in the setting of sepsis). Moreover, chronic inflammation is generally deleterious and is at the root of numerous chronic diseases, causing severe and irreversible damage to tissues. In such settings, the immune response is often directed against self-tissues (autoimmunity), although chronic responses to foreign entities can also lead to bystander damage to self tissues.

The aim of anti-inflammatory therapy is therefore to reduce this inflammation, to inhibit autoimmunity when present and to allow for the physiological process or healing and tissue repair to progress.

The agents may be used to treat inflammation of any tissue and organs of the body, including musculoskeletal inflammation, vascular inflammation, neural inflammation, digestive system inflammation, ocular inflammation, inflammation of the reproductive system, and other inflammation, as exemplified below.

Musculoskeletal inflammation refers to any inflammatory condition of the musculoskeletal system, particularly those conditions affecting skeletal joints, including joints of the hand, wrist, elbow, shoulder, jaw, spine, neck, hip, knew, ankle, and foot, and conditions affecting tissues connecting muscles to bones such as tendons. Examples of musculoskeletal inflammation which may be treated with compounds of the invention include arthritis (including, for example, osteoarthritis, rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, acute and chronic infectious arthritis, arthritis associated with gout and pseudogout, and juvenile idiopathic arthritis), tendonitis, synovitis, tenosynovitis, bursitis, fibrositis (fibromyalgia), epicondylitis, myositis, and osteitis (including, for example, Paget's disease, osteitis pubis, and osteitis fibrosa cystic).

Ocular inflammation refers to inflammation of any structure of the eye, including the eye lids. Examples of ocular inflammation which may be treated with the compounds of the invention include blepharitis, blepharochalasis, conjunctivitis, dacryoadenitis, keratitis, keratoconjunctivitis sicca (dry eye), scleritis, trichiasis, and uveitis.

Examples of inflammation of the nervous system which may be treated with the compounds of the invention include encephalitis, Guillain-Barre syndrome, meningitis, neuromyotonia, narcolepsy, multiple sclerosis, myelitis and schizophrenia.

Examples of inflammation of the vasculature or lymphatic system which may be treated with the compounds of the invention include arthrosclerosis, arthritis, phlebitis, vasculitis, and lymphangitis.

Examples of inflammatory conditions of the digestive system which may be treated with the compounds of the invention include cholangitis, cholecystitis, enteritis, enterocolitis, gastritis, gastroenteritis, inflammatory bowel disease (such as Crohn's disease and ulcerative colitis), ileitis, and proctitis.

Examples of inflammatory conditions of the reproductive system which may be treated with the compounds of the invention include cervicitis, chorioamnionitis, endometritis, epididymitis, omphalitis, oophoritis, orchitis, salpingitis, tubo-ovarian abscess, urethritis, vaginitis, vulvitis, and vulvodynia.

The agents may be used to treat autoimmune conditions having an inflammatory component. Such conditions include acute disseminated alopecia universalise, Behcet's disease, Chagas' disease, chronic fatigue syndrome, dysautonomia, encephalomyelitis, ankylosing spondylitis, aplastic anemia, hidradenitis suppurativa, autoimmune hepatitis, autoimmune oophoritis, celiac disease, Crohn's disease, diabetes mellitus type 1, giant cell arteritis, goodpasture's syndrome, Grave's disease, Guillain-Barre syndrome, Hashimoto's disease, Henoch-Schönlein purpura, Kawasaki's disease, lupus erythematosus, microscopic colitis, microscopic polyarteritis, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, opsocionus myoclonus syndrome, optic neuritis, ord's thyroiditis, pemphigus, polyarteritis nodosa, polymyalgia, rheumatoid arthritis, Reiter's syndrome, Sjogren's syndrome, temporal arteritis, Wegener's granulomatosis, warm autoimmune haemolytic anemia, interstitial cystitis, lyme disease, morphea, psoriasis, sarcoidosis, scleroderma, ulcerative colitis, and vitiligo.

The agents may be used to treat T-cell mediated hypersensitivity diseases having an inflammatory component. Such conditions include contact hypersensitivity, contact dermatitis (including that due to poison ivy), uticaria, skin allergies, respiratory allergies (hayfever, allergic rhinitis) and gluten-sensitive enteropathy (Celliac disease).

Other inflammatory conditions which may be treated with the agents include, for example, appendicitis, dermatitis, dermatomyositis, endocarditis, fibrositis, gingivitis, glossitis, hepatitis, hidradenitis suppurativa, iritis, laryngitis, mastitis, myocarditis, nephritis, otitis, pancreatitis, parotitis, percarditis, peritonoitis, pharyngitis, pleuritis, pneumonitis, prostatistis, pyelonephritis, and stomatisi, transplant rejection (involving organs such as kidney, liver, heart, lung, pancreas (e.g., islet cells), bone marrow, cornea, small bowel, skin allografts, skin homografts, and heart valve xengrafts, sewrum sickness, and graft vs host disease), acute pancreatitis, chronic pancreatitis, acute respiratory distress syndrome, Sexary's syndrome, congenital adrenal hyperplasis, nonsuppurative thyroiditis, hypercalcemia associated with cancer, pemphigus, bullous dermatitis herpetiformis, severe erythema multiforme, exfoliative dermatitis, seborrheic dermatitis, seasonal or perennial allergic rhinitis, bronchial asthma, contact dermatitis, astopic dermatitis, drug hypersensistivity reactions, allergic conjunctivitis, keratitis, herpes zoster ophthalmicus, iritis and oiridocyclitis, chorioretinitis, optic neuritis, symptomatic sarcoidosis, fulminating or disseminated pulmonary tuberculosis chemotherapy, idiopathic thrombocytopenic purpura in adults, secondary thrombocytopenia in adults, acquired (autroimmine) haemolytic anemia, leukaemia and lymphomas in adults, acute leukaemia of childhood, regional enteritis, autoimmune vasculitis, multiple sclerosis, chronic obstructive pulmonary disease, solid organ transplant rejection, sepsis. Preferred treatments include treatment of transplant rejection, rheumatoid arthritis, psoriatic arthritis, multiple sclerosis, Type 1 diabetes, asthma, inflammatory bowel disease, systemic lupus erythematosis, psoriasis, chronic pulmonary disease, and inflammation accompanying infectious conditions (e.g., sepsis).

In a further aspect of the invention there is provided a compound of formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of inflammation, allergy and autoimmune disease

In a further aspect there is provided a method of treating inflammation, allergy and autoimmune disease comprising administering to a human in need thereof a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of inflammation, allergy and autoimmune disease.

In one aspect the disease to be treated is asthma.

The compounds of formula (I) and pharmaceutically acceptable salts thereof may be used in combination with one or more other agents which may be useful in the prevention or treatment of allergic disease, inflammatory disease, autoimmune disease, for example; antigen immunotherapy, anti-histamines, steroids, NSAIDs, bronchodilators (e.g. beta 2 agonists, adrenergic agonists, anticholinergic agents, theophylline), methotrexate, leukotriene modulators and similar agents; monoclonal antibody therapy such as anti-IgE, anti-TNF, anti-IL-5, anti-IL-6, anti-IL-12, anti-IL-1 and similar agents; receptor therapies e.g. entanercept and similar agents; antigen non-specific immunotherapies (e.g. interferon or other cytokines/chemokines, cytokine/chemokine receptor modulators, cytokine agonists or antagonists, TLR agonists and similar agents).

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease for use in therapy.

In a further aspect there is provided a combination comprising a compound of formula (I) or pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease, for use in the treatment of allergic disease, inflammation or autoimmune disease

In a further aspect there is provided the use of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease in the manufacture of a medicament for the treatment of allergic disease, inflammation or autoimmune disease

In a further aspect there is provided a method of treating allergic disease, inflammation or autoimmune disease comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease.

In a further aspect there is provided a pharmaceutical composition comprising a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of allergic disease, inflammation or autoimmune disease and one or more of pharmaceutically acceptable excipients.

In one aspect the disease to be treated with such a combination is asthma.

In one aspect the disease or condition to be treated is cancer.

Examples of cancer diseases and conditions in which compounds of formula (I), or pharmaceutically acceptable salts or solvates thereof may have potentially beneficial antitumour effects include, but are not limited to, cancers of the lung, bone, pancreas, skin, head, neck, uterus, ovaries, stomach, colon, breast, esophagus, small intestine, bowel, endocrine system, thyroid glad, parathyroid gland, adrenal gland, urethra, prostate, penis, testes, ureter, bladder, kidney or liver; rectal cancer; cancer of the anal region; carcinomas of the fallopian tubes, endometrium, cervix, vagina, vulva, renal pelvis, renal cell; sarcoma of soft tissue; myxoma; rhabdomyoma; fibroma; lipoma; teratoma; cholangiocarcinoma; hepatoblastoma; angiosarcoma; hemagioma; hepatoma; fibrosarcoma; chondrosarcoma; myeloma; chronic or acute leukemia; lymphocytic lymphomas; primary CNS lymphoma; neoplasms of the CNS; spinal axis tumours; squamous cell carcinomas; synovial sarcoma; malignant pleural mesotheliomas; brain stem glioma; pituitary adenoma; bronchial adenoma; chondromatous hanlartoma; inesothelioma; Hodgkin's Disease or a combination of one or more of the foregoing cancers.

The compounds of the present invention may also be useful in the treatment of one or more diseases afflicting mammals which are characterized by cellular proliferation in the area of disorders associated with neo-vascularization and/or vascular permeability including blood vessel proliferative disorders including arthritis (rheumatoid arthritis) and restenosis; fibrotic disorders including hepatic cirrhosis and atherosclerosis; mesangial cell proliferative disorders include glomerulonephritis, diabetic nephropathy, malignant nephrosclerosis, thrombotic microangiopathy syndromes, proliferative retinopathies, organ transplant rejection and glomerulopathies; and metabolic disorders include psoriasis, diabetes mellitus, chronic wound healing, inflammation and neurodegenerative diseases.

In a further aspect of the invention there is provided a compound of formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of cancer.

In a further aspect there is provided a method of treating cancer comprising administering to a human in need thereof a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of cancer.

In one embodiment, the compound of the invention may be employed with other therapeutic methods of cancer treatment. In particular, in anti-neoplastic therapy, combination therapy with other chemotherapeutic, hormonal, antibody agents as well as surgical and/or radiation treatments other than those mentioned above are envisaged.

In one embodiment, the further anti-cancer therapy is surgical and/or radiotherapy.

In one embodiment, the further anti-cancer therapy is at least one additional anti-neoplastic agent.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, for use in therapy.

In a further aspect there is provided a combination comprising a compound of formula (I) or pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, for use in treating cancer.

In a further aspect there is provided the use of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, in the manufacture of a medicament for the treatment of cancer.

In a further aspect there is provided a method of treating cancer, comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent.

In a further aspect there is provided a pharmaceutical composition comprising a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent, particularly at least one anti-neoplastic agent and one or more of pharmaceutically acceptable carriers, diluents and excipients.

Any anti-neoplastic agent that has activity versus a susceptible tumor being treated may be utilized in the combination. Typical anti-neoplastic agents useful include, but are not limited to, anti-microtubule agents such as diterpenoids and vinca alkaloids; platinum coordination complexes; alkylating agents such as nitrogen mustards, oxazaphosphorines, alkylsulfonates, nitrosoureas, and triazenes; antibiotic agents such as anthracyclins, actinomycins and bleomycins; topoisomerase II inhibitors such as epipodophyllotoxins; antimetabolites such as purine and pyrimidine analogues and anti-folate compounds; topoisomerase I inhibitors such as camptothecins; hormones and hormonal analogues; signal transduction pathway inhibitors; non-receptor tyrosine angiogenesis inhibitors; immunotherapeutic agents; proapoptotic agents; and cell cycle signaling inhibitors.

Anti-Microtubule or Anti-Mitotic Agents:

Anti-microtubule or anti-mitotic agents are phase specific agents active against the microtubules of tumor cells during M or the mitosis phase of the cell cycle. Examples of anti-microtubule agents include, but are not limited to, diterpenoids and vinca alkaloids.

Diterpenoids, which are derived from natural sources, are phase specific anti-cancer agents that operate at the G₂/M phases of the cell cycle. It is believed that the diterpenoids stabilize the β-tubulin subunit of the microtubules, by binding with this protein. Disassembly of the protein appears then to be inhibited with mitosis being arrested and cell death following. Examples of diterpenoids include, but are not limited to, paclitaxel and its analog docetaxel.

Paclitaxel, 5β,20-epoxy-1,2α,4,7β,10β,13α-hexa-hydroxytax-11-en-9-one 4,10-diacetate 2-benzoate 13-ester with (2R,3S)—N-benzoyl-3-phenylisoserine; is a natural diterpene product isolated from the Pacific yew tree Taxus brevifolia and is commercially available as an injectable solution TAXOL®. It is a member of the taxane family of terpenes. Paclitaxel has been approved for clinical use in the treatment of refractory ovarian cancer in the United States (Markman et al., Yale Journal of Biology and Medicine, 64:583, 1991; McGuire et al., Ann. Intern, Med., 111:273, 1989) and for the treatment of breast cancer (Holmes et al., J. Nat. Cancer Inst., 83:1797, 1991.) It is a potential candidate for treatment of neoplasms in the skin (Einzig et. al., Proc. Am. Soc. Clin. Oncol., 20:46) and head and neck carcinomas (Forastire et. al., Sem. Oncol., 20:56, 1990). The compound also shows potential for the treatment of polycystic kidney disease (Woo et. al., Nature, 368:750. 1994), lung cancer and malaria. Treatment of patients with paclitaxel results in bone marrow suppression (multiple cell lineages, Ignoff, R. J. et. al, Cancer Chemotherapy Pocket Guide, 1998) related to the duration of dosing above a threshold concentration (50 nM) (Kearns, C. M. et. al., Seminars in Oncology, 3(6) p. 16-23, 1995).

Docetaxel, (2R,3S)—N-carboxy-3-phenylisoserine,N-tert-butyl ester, 13-ester with 5β-20-epoxy-1,2α,4,7β,10β,13α-hexahydroxytax-11-en-9-one 4-acetate 2-benzoate, trihydrate; is commercially available as an injectable solution as TAXOTERE®. Docetaxel is indicated for the treatment of breast cancer. Docetaxel is a semisynthetic derivative of paclitaxel q.v., prepared using a natural precursor, 10-deacetyl-baccatin III, extracted from the needle of the European Yew tree.

Vinca alkaloids are phase specific anti-neoplastic agents derived from the periwinkle plant. Vinca alkaloids act at the M phase (mitosis) of the cell cycle by binding specifically to tubulin. Consequently, the bound tubulin molecule is unable to polymerize into microtubules. Mitosis is believed to be arrested in metaphase with cell death following. Examples of vinca alkaloids include, but are not limited to, vinblastine, vincristine, and vinorelbine.

Vinblastine, vincaleukoblastine sulfate, is commercially available as VELBAN® as an injectable solution. Although, it has possible indication as a second line therapy of various solid tumors, it is primarily indicated in the treatment of testicular cancer and various lymphomas including Hodgkin's Disease; and lymphocytic and histiocytic lymphomas. Myelosuppression is the dose limiting side effect of vinblastine.

Vincristine, vincaleukoblastine, 22-oxo-, sulfate, is commercially available as ONCOVIN® as an injectable solution. Vincristine is indicated for the treatment of acute leukemias and has also found use in treatment regimens for Hodgkin's and non-Hodgkin's malignant lymphomas. Alopecia and neurologic effects are the most common side effect of vincristine and to a lesser extent myelosupression and gastrointestinal mucositis effects occur.

Vinorelbine, 3′,4′-didehydro-4‘-deoxy-C’-norvincaleukoblastine [R—(R*,R*)-2,3-dihydroxybutanedioate (1:2)(salt)], commercially available as an injectable solution of vinorelbine tartrate (NAVELBINE®), is a semisynthetic vinca alkaloid. Vinorelbine is indicated as a single agent or in combination with other chemotherapeutic agents, such as cisplatin, in the treatment of various solid tumors, particularly non-small cell lung, advanced breast, and hormone refractory prostate cancers. Myelosuppression is the most common dose limiting side effect of vinorelbine.

Platinum Coordination Complexes:

Platinum coordination complexes are non-phase specific anti-cancer agents, which are interactive with DNA. The platinum complexes enter tumor cells, undergo, aquation and form intra- and interstrand crosslinks with DNA causing adverse biological effects to the tumor. Examples of platinum coordination complexes include, but are not limited to, oxaliplatin, cisplatin and carboplatin.

Cisplatin, cis-diamminedichloroplatinum, is commercially available as PLATINOL® as an injectable solution. Cisplatin is primarily indicated in the treatment of metastatic testicular and ovarian cancer and advanced bladder cancer.

Carboplatin, platinum, diammine [1,1-cyclobutane-dicarboxylate(2-)—O,O′], is commercially available as PARAPLATIN® as an injectable solution. Carboplatin is primarily indicated in the first and second line treatment of advanced ovarian carcinoma.

Alkylating Agents:

Alkylating agents are non-phase anti-cancer specific agents and strong electrophiles. Typically, alkylating agents form covalent linkages, by alkylation, to DNA through nucleophilic moieties of the DNA molecule such as phosphate, amino, sulfhydryl, hydroxyl, carboxyl, and imidazole groups. Such alkylation disrupts nucleic acid function leading to cell death. Examples of alkylating agents include, but are not limited to, nitrogen mustards such as cyclophosphamide, melphalan, and chlorambucil; alkyl sulfonates such as busulfan; nitrosoureas such as carmustine; and triazenes such as dacarbazine.

Cyclophosphamide, 2-[bis(2-chloroethyl)amino]tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide monohydrate, is commercially available as an injectable solution or tablets as CYTOXAN®. Cyclophosphamide is indicated as a single agent or in combination with other chemotherapeutic agents, in the treatment of malignant lymphomas, multiple myeloma, and leukemias.

Melphalan, 4-[bis(2-chloroethyl)amino]-L-phenylalanine, is commercially available as an injectable solution or tablets as ALKERAN®. Melphalan is indicated for the palliative treatment of multiple myeloma and non-resectable epithelial carcinoma of the ovary. Bone marrow suppression is the most common dose limiting side effect of melphalan.

Chlorambucil, 4-[bis(2-chloroethyl)amino]benzenebutanoic acid, is commercially available as LEUKERAN® tablets. Chlorambucil is indicated for the palliative treatment of chronic lymphatic leukemia, and malignant lymphomas such as lymphosarcoma, giant follicular lymphoma, and Hodgkin's disease.

Busulfan, 1,4-butanediol dimethanesulfonate, is commercially available as MYLERAN® TABLETS. Busulfan is indicated for the palliative treatment of chronic myelogenous leukemia.

Carmustine, 1,3-[bis(2-chloroethyl)-1-nitrosourea, is commercially available as single vials of lyophilized material as BiCNU®. Carmustine is indicated for the palliative treatment as a single agent or in combination with other agents for brain tumors, multiple myeloma, Hodgkin's disease, and non-Hodgkin's lymphomas.

Dacarbazine, 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide, is commercially available as single vials of material as DTIC-Dome®. Dacarbazine is indicated for the treatment of metastatic malignant melanoma and in combination with other agents for the second line treatment of Hodgkin's Disease.

Antibiotic Anti-Neoplastics

Antibiotic anti-neoplastics are non-phase specific agents, which bind or intercalate with DNA. Typically, such action results in stable DNA complexes or strand breakage, which disrupts ordinary function of the nucleic acids leading to cell death. Examples of antibiotic anti-neoplastic agents include, but are not limited to, actinomycins such as dactinomycin, anthrocyclins such as daunorubicin and doxorubicin; and bleomycins.

Dactinomycin, also known as Actinomycin D, is commercially available in injectable form as COSMEGEN®. Dactinomycin is indicated for the treatment of Wilm's tumor and rhabdomyosarcoma.

Daunorubicin, (8S-cis-)-8-acetyl-10-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexopyranosyl)oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12 naphthacenedione hydrochloride, is commercially available as a liposomal injectable form as DAUNOXOME® or as an injectable as CERUBIDINE®. Daunorubicin is indicated for remission induction in the treatment of acute nonlymphocytic leukemia and advanced HIV associated Kaposi's sarcoma.

Doxorubicin, (8S, 10S)-10-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexopyranosyl)oxy]-8-glycoloyl, 7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12 naphthacenedione hydrochloride, is commercially available as an injectable form as RUBEX® or ADRIAMYCIN RDF®. Doxorubicin is primarily indicated for the treatment of acute lymphoblastic leukemia and acute myeloblastic leukemia, but is also a useful component in the treatment of some solid tumors and lymphomas.

Bleomycin, a mixture of cytotoxic glycopeptide antibiotics isolated from a strain of Streptomyces verticillus, is commercially available as BLENOXANE®. Bleomycin is indicated as a palliative treatment, as a single agent or in combination with other agents, of squamous cell carcinoma, lymphomas, and testicular carcinomas.

Topoisomerase II Inhibitors:

Topoisomerase II inhibitors include, but are not limited to, epipodophyllotoxins.

Epipodophyllotoxins are phase specific anti-neoplastic agents derived from the mandrake plant. Epipodophyllotoxins typically affect cells in the S and G₂ phases of the cell cycle by forming a ternary complex with topoisomerase II and DNA causing DNA strand breaks. The strand breaks accumulate and cell death follows. Examples of epipodophyllotoxins include, but are not limited to, etoposide and teniposide.

Etoposide, 4′-demethyl-epipodophyllotoxin 9[4,6-0-(R)-ethylidene-β-D-glucopyranoside], is commercially available as an injectable solution or capsules as VePESID® and is commonly known as VP-16. Etoposide is indicated as a single agent or in combination with other chemotherapy agents in the treatment of testicular and non-small cell lung cancers.

Teniposide, 4′-demethyl-epipodophyllotoxin 9[4,6-0-(R)-thenylidene-β-D-glucopyranoside], is commercially available as an injectable solution as VUMON® and is commonly known as VM-26. Teniposide is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia in children.

Antimetabolite Neoplastic Agents:

Antimetabolite neoplastic agents are phase specific anti-neoplastic agents that act at S phase (DNA synthesis) of the cell cycle by inhibiting DNA synthesis or by inhibiting purine or pyrimidine base synthesis and thereby limiting DNA synthesis. Consequently, S phase does not proceed and cell death follows. Examples of antimetabolite anti-neoplastic agents include, but are not limited to, fluorouracil, methotrexate, cytarabine, mecaptopurine, thioguanine, and gemcitabine.

5-fluorouracil, 5-fluoro-2,4-(1H,3H) pyrimidinedione, is commercially available as fluorouracil. Administration of 5-fluorouracil leads to inhibition of thymidylate synthesis and is also incorporated into both RNA and DNA. The result typically is cell death. 5-fluorouracil is indicated as a single agent or in combination with other chemotherapy agents in the treatment of carcinomas of the breast, colon, rectum, stomach and pancreas. Other fluoropyrimidine analogs include 5-fluoro deoxyuridine (floxuridine) and 5-fluorodeoxyuridine monophosphate.

Cytarabine, 4-amino-1-β-D-arabinofuranosyl-2 (1H)-pyrimidinone, is commercially available as CYTOSAR-U® and is commonly known as Ara-C. It is believed that cytarabine exhibits cell phase specificity at S-phase by inhibiting DNA chain elongation by terminal incorporation of cytarabine into the growing DNA chain. Cytarabine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. Other cytidine analogs include 5-azacytidine and 2′,2′-difluorodeoxycytidine (gemcitabine).

Mercaptopurine, 1,7-dihydro-6H-purine-6-thione monohydrate, is commercially available as PURINETHOL®. Mercaptopurine exhibits cell phase specificity at S-phase by inhibiting DNA synthesis by an as of yet unspecified mechanism. Mercaptopurine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. A useful mercaptopurine analog is azathioprine.

Thioguanine, 2-amino-1,7-dihydro-6H-purine-6-thione, is commercially available as TABLOID®. Thioguanine exhibits cell phase specificity at S-phase by inhibiting DNA synthesis by an as of yet unspecified mechanism. Thioguanine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. Other purine analogs include pentostatin, erythrohydroxynonyladenine, fludarabine phosphate, and cladribine.

Gemcitabine, 2′-deoxy-2′, 2′-difluorocytidine monohydrochloride (f-isomer), is commercially available as GEMZAR®. Gemcitabine exhibits cell phase specificity at S-phase and by blocking progression of cells through the G1/S boundary. Gemcitabine is indicated in combination with cisplatin in the treatment of locally advanced non-small cell lung cancer and alone in the treatment of locally advanced pancreatic cancer.

Methotrexate, N-[4[[(2,4-diamino-6-pteridinyl) methyl]methylamino] benzoyl]-L-glutamic acid, is commercially available as methotrexate sodium. Methotrexate exhibits cell phase effects specifically at S-phase by inhibiting DNA synthesis, repair and/or replication through the inhibition of dyhydrofolic acid reductase which is required for synthesis of purine nucleotides and thymidylate. Methotrexate is indicated as a single agent or in combination with other chemotherapy agents in the treatment of choriocarcinoma, meningeal leukemia, non-Hodgkin's lymphoma, and carcinomas of the breast, head, neck, ovary and bladder.

Topoisomerase I Inhibitors:

Camptothecins, including, camptothecin and camptothecin derivatives are available or under development as Topoisomerase I inhibitors. Camptothecins cytotoxic activity is believed to be related to its Topoisomerase I inhibitory activity. Examples of camptothecins include, but are not limited to irinotecan, topotecan, and the various optical forms of 7-(4-methylpiperazino-methylene)-10,11-ethylenedioxy-20-camptothecin described below.

Irinotecan HCl, (4S)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino) carbonyloxy]-1H-pyrano[3′,4′,6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione hydrochloride, is commercially available as the injectable solution CAMPTOSAR®. Irinotecan is a derivative of camptothecin which binds, along with its active metabolite SN-38, to the topoisomerase I-DNA complex. It is believed that cytotoxicity occurs as a result of irreparable double strand breaks caused by interaction of the topoisomerase I:DNA:irintecan or SN-38 ternary complex with replication enzymes. Irinotecan is indicated for treatment of metastatic cancer of the colon or rectum.

Topotecan HCl, (S)-10-[(dimethylamino)methyl]-4-ethyl-4,9-dihydroxy-1H-pyrano[3′,4′,6,7]indolizino[1,2-b]quinoline-3,14-(4H,12H)-dione monohydrochloride, is commercially available as the injectable solution HYCAMTIN®. Topotecan is a derivative of camptothecin which binds to the topoisomerase I-DNA complex and prevents religation of singles strand breaks caused by Topoisomerase I in response to torsional strain of the DNA molecule. Topotecan is indicated for second line treatment of metastatic carcinoma of the ovary and small cell lung cancer.

Hormones and Hormonal Analogues:

Hormones and hormonal analogues are useful compounds for treating cancers in which there is a relationship between the hormone(s) and growth and/or lack of growth of the cancer. Examples of hormones and hormonal analogues useful in cancer treatment include, but are not limited to, adrenocorticosteroids such as prednisone and prednisolone which are useful in the treatment of malignant lymphoma and acute leukemia in children; aminoglutethimide and other aromatase inhibitors such as anastrozole, letrazole, vorazole, and exemestane useful in the treatment of adrenocortical carcinoma and hormone dependent breast carcinoma containing estrogen receptors; progestrins such as megestrol acetate useful in the treatment of hormone dependent breast cancer and endometrial carcinoma; estrogens, estrogens, and anti-estrogens such as fulvestrant, flutamide, nilutamide, bicalutamide, cyproterone acetate and 5α-reductases such as finasteride and dutasteride, useful in the treatment of prostatic carcinoma and benign prostatic hypertrophy; anti-estrogens such as tamoxifen, toremifene, raloxifene, droloxifene, iodoxyfene, as well as selective estrogen receptor modulators (SERMS) such those described in U.S. Pat. Nos. 5,681,835, 5,877,219, and 6,207,716, useful in the treatment of hormone dependent breast carcinoma and other susceptible cancers; and gonadotropin-releasing hormone (GnRH) and analogues thereof which stimulate the release of leutinizing hormone (LH) and/or follicle stimulating hormone (FSH) for the treatment prostatic carcinoma, for instance, LHRH agonists and antagagonists such as goserelin acetate and luprolide.

Signal Transduction Pathway Inhibitors:

Signal transduction pathway inhibitors are those inhibitors, which block or inhibit a chemical process which evokes an intracellular change. As used herein this change is cell proliferation or differentiation. Signal tranduction inhibitors useful in the present invention include inhibitors of receptor tyrosine kinases, non-receptor tyrosine kinases, SH2/SH3domain blockers, serine/threonine kinases, phosphotidyl inositol-3 kinases, myo-inositol signaling, and Ras oncogenes.

Several protein tyrosine kinases catalyse the phosphorylation of specific tyrosyl residues in various proteins involved in the regulation of cell growth. Such protein tyrosine kinases can be broadly classified as receptor or non-receptor kinases.

Receptor tyrosine kinases are transmembrane proteins having an extracellular ligand binding domain, a transmembrane domain, and a tyrosine kinase domain. Receptor tyrosine kinases are involved in the regulation of cell growth and are generally termed growth factor receptors. Inappropriate or uncontrolled activation of many of these kinases, i.e. aberrant kinase growth factor receptor activity, for example by over-expression or mutation, has been shown to result in uncontrolled cell growth. Accordingly, the aberrant activity of such kinases has been linked to malignant tissue growth. Consequently, inhibitors of such kinases could provide cancer treatment methods. Growth factor receptors include, for example, epidermal growth factor receptor (EGFr), platelet derived growth factor receptor (PDGFr), erbB2, erbB4, ret, vascular endothelial growth factor receptor (VEGFr), tyrosine kinase with immunoglobulin-like and epidermal growth factor homology domains (TIE-2), insulin growth factor-I (IGFI) receptor, macrophage colony stimulating factor (cfms), BTK, ckit, cmet, fibroblast growth factor (FGF) receptors, Trk receptors (TrkA, TrkB, and TrkC), ephrin (eph) receptors, and the RET protooncogene. Several inhibitors of growth receptors are under development and include ligand antagonists, antibodies, tyrosine kinase inhibitors and anti-sense oligonucleotides. Growth factor receptors and agents that inhibit growth factor receptor function are described, for instance, in Kath, John C., Exp. Opin. Ther. Patents (2000) 10(6):803-818; Shawver et al DDT Vol 2, No. 2 Feb. 1997; and Lofts, F. J. et al, “Growth factor receptors as targets”, New Molecular Targets for Cancer Chemotherapy, ed. Workman, Paul and Kerr, David, CRC press 1994, London.

Tyrosine kinases, which are not growth factor receptor kinases are termed non-receptor tyrosine kinases. Non-receptor tyrosine kinases useful in the present invention, which are targets or potential targets of anti-cancer drugs, include cSrc, Lck, Fyn, Yes, Jak, cAbl, FAK (Focal adhesion kinase), Brutons tyrosine kinase, and Bcr-Abl. Such non-receptor kinases and agents which inhibit non-receptor tyrosine kinase function are described in Sinh, S. and Corey, S. J., (1999) Journal of Hematotherapy and Stem Cell Research 8 (5): 465-80; and Bolen, J. B., Brugge, J. S., (1997) Annual review of Immunology. 15: 371-404.

SH2/SH3 domain blockers are agents that disrupt SH2 or SH3 domain binding in a variety of enzymes or adaptor proteins including, PI3-K p85 subunit, Src family kinases, adaptor molecules (Shc, Crk, Nck, Grb2) and Ras-GAP. SH2/SH3 domains as targets for anti-cancer drugs are discussed in Smithgall, T. E. (1995), Journal of Pharmacological and Toxicological Methods. 34(3) 125-32.

Inhibitors of Serine/Threonine Kinases including MAP kinase cascade blockers which include blockers of Raf kinases (rafk), Mitogen or Extracellular Regulated Kinase (MEKs), and Extracellular Regulated Kinases (ERKs); and Protein kinase C family member blockers including blockers of PKCs (alpha, beta, gamma, epsilon, mu, lambda, iota, zeta). IkB kinase family (IKKa, IKKb), PKB family kinases, akt kinase family members, and TGF beta receptor kinases. Such Serine/Threonine kinases and inhibitors thereof are described in Yamamoto, T., Taya, S., Kaibuchi, K., (1999), Journal of Biochemistry. 126 (5) 799-803; Brodt, P, Samani, A., and Navab, R. (2000), Biochemical Pharmacology, 60. 1101-1107; Massague, J., Weis-Garcia, F. (1996) Cancer Surveys. 27:41-64; Philip, P. A., and Harris, A. L. (1995), Cancer Treatment and Research. 78: 3-27, Lackey, K. et al Bioorganic and Medicinal Chemistry Letters, (10), 2000, 223-226; U.S. Pat. No. 6,268,391; and Martinez-Iacaci, L., et al, Int. J. Cancer (2000), 88(1), 44-52.

Inhibitors of Phosphotidyl inositol-3 Kinase family members including blockers of PI3-kinase, ATM, DNA-PK, and Ku are also useful in the present invention. Such kinases are discussed in Abraham, R. T. (1996), Current Opinion in Immunology. 8 (3) 412-8; Canman, C. E., Lim, D. S. (1998), Oncogene 17 (25) 3301-3308; Jackson, S. P. (1997), International Journal of Biochemistry and Cell Biology. 29 (7):935-8; and Zhong, H. et al, Cancer res, (2000) 60(6), 1541-1545.

Also useful in the present invention are Myo-inositol signaling inhibitors such as phospholipase C blockers and Myoinositol analogues. Such signal inhibitors are described in Powis, G., and Kozikowski A., (1994) New Molecular Targets for Cancer Chemotherapy ed., Paul Workman and David Kerr, CRC press 1994, London.

Another group of signal transduction pathway inhibitors are inhibitors of Ras Oncogene. Such inhibitors include inhibitors of farnesyltransferase, geranyl-geranyl transferase, and CAAX proteases as well as anti-sense oligonucleotides, ribozymes and immunotherapy. Such inhibitors have been shown to block ras activation in cells containing wild type mutant ras, thereby acting as antiproliferation agents. Ras oncogene inhibition is discussed in Scharovsky, O. G., Rozados, V. R., Gervasoni, S. I. Matar, P. (2000), Journal of Biomedical Science. 7(4) 292-8; Ashby, M. N. (1998), Current Opinion in Lipidology. 9 (2) 99-102; and BioChim. Biophys. Acta, (19899) 1423(3):19-30.

As mentioned above, antibody antagonists to receptor kinase ligand binding may also serve as signal transduction inhibitors. This group of signal transduction pathway inhibitors includes the use of humanized antibodies to the extracellular ligand binding domain of receptor tyrosine kinases. For example Imclone C225 EGFR specific antibody (see Green, M. C. et al, Monoclonal Antibody Therapy for Solid Tumors, Cancer Treat. Rev., (2000), 26(4), 269-286); Herceptin® erbB2 antibody (see Tyrosine Kinase Signalling in Breast cancer:erbB Family Receptor Tyrosine Kinases, Breast cancer Res., 2000, 2(3), 176-183); and 2CB VEGFR2 specific antibody (see Brekken, R. A. et al, Selective Inhibition of VEGFR2 Activity by a monoclonal Anti-VEGF antibody blocks tumor growth in mice, Cancer Res. (2000) 60, 5117-5124).

Anti-Angiogenic Agents:

(i) Anti-angiogenic agents including non-receptor MEK angiogenesis inhibitors may alo be useful. Anti-angiogenic agents such as those which inhibit the effects of vascular edothelial growth factor, (for example the anti-vascular endothelial cell growth factor antibody bevacizumab [Avastin™], and compounds that work by other mechanisms (for example linomide, inhibitors of integrin αvβ3 function, endostatin and angiostatin); Immunotherapeutic Agents:

Agents used in immunotherapeutic regimens may also be useful in combination with the compounds of formula (I). Immunotherapy approaches, including for example ex-vivo and in-vivo approaches to increase the immunogenecity of patient tumour cells, such as transfection with cytokines such as interleukin 2, interleukin 4 or granulocyte-macrophage colony stimulating factor, approaches to decrease T-cell anergy, approaches using transfected immune cells such as cytokine-transfected dendritic cells, approaches using cytokine-transfected tumour cell lines and approaches using anti-idiotypic antibodies

Proapoptotic Agents:

Agents used in proapoptotic regimens (e.g., bcl-2 antisense oligonucleotides) may also be used in the combination of the present invention.

Cell Cycle Signalling Inhibitors

Cell cycle signalling inhibitors inhibit molecules involved in the control of the cell cycle. A family of protein kinases called cyclin dependent kinases (CDKs) and their interaction with a family of proteins termed cyclins controls progression through the eukaryotic cell cycle. The coordinate activation and inactivation of different cyclin/CDK complexes is necessary for normal progression through the cell cycle. Several inhibitors of cell cycle signalling are under development. For instance, examples of cyclin dependent kinases, including CDK2, CDK4, and CDK6 and inhibitors for the same are described in, for instance, Rosania et al, Exp. Opin. Ther. Patents (2000) 10(2):215-230.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent selected from anti-microtubule agents, platinum coordination complexes, alkylating agents, antibiotic agents, topoisomerase II inhibitors, antimetabolites, topoisomerase I inhibitors, hormones and hormonal analogues, signal transduction pathway inhibitors, non-receptor tyrosine MEK angiogenesis inhibitors, immunotherapeutic agents, proapoptotic agents, and cell cycle signaling inhibitors.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent which is an anti-microtubule agent selected from diterpenoids and vinca alkaloids.

In a further embodiment, at least one anti-neoplastic agent is a diterpenoid.

In a further embodiment, at least one anti-neoplastic agent is a vinca alkaloid.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent, which is a platinum coordination complex.

In a further embodiment, at least one anti-neoplastic agent is paclitaxel, carboplatin, or vinorelbine.

In a further embodiment, at least one anti-neoplastic agent is carboplatin.

In a further embodiment, at least one anti-neoplastic agent is vinorelbine.

In a further embodiment, at least one anti-neoplastic agent is paclitaxel.

In one embodiment, the combination of the present invention comprises a compound of formula I and salts or solvates thereof and at least one anti-neoplastic agent which is a signal transduction pathway inhibitor.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a growth factor receptor kinase VEGFR2, TIE2, PDGFR, BTK, erbB2, EGFr, IGFR-1, TrkA, TrkB, TrkC, or c-fms.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a serine/threonine kinase rafk, akt, or PKC-zeta.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a non-receptor tyrosine kinase selected from the src family of kinases.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of c-src.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of Ras oncogene selected from inhibitors of farnesyl transferase and geranylgeranyl transferase.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a serine/threonine kinase selected from the group consisting of PI3K.

In a further embodiment the signal transduction pathway inhibitor is a dual EGFr/erbB2 inhibitor, for example N-{3-Chloro-4-[(3-fluorobenzyl) oxy]phenyl}-6-[5-({[2-(methanesulphonyl) ethyl]amino}methyl)-2-furyl]-4-quinazolinamine (structure below):

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent which is a cell cycle signaling inhibitor.

In further embodiment, cell cycle signaling inhibitor is an inhibitor of CDK2, CDK4 or CDK6.

In one aspect the disease to be treated is an infectious disease, eg caused by bacteria or virus

In a further aspect of the invention there is provided a compound of formula (I) or a pharmaceutically acceptable salt thereof for use in the treatment of infectious disease.

In a further aspect there is provided a method of treating infectious disease comprising administering to a human in need thereof a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect there is provided the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for the treatment of infectious disease.

In one embodiment, the compound of the invention may be employed with other therapeutic methods of treating infectious disease. In particular, antiviral and antibacterial agents are envisaged

The compounds of formula (I) and pharmaceutically acceptable salts thereof may be used in combination with one or more agents useful in the prevention or treatment of bacterial and viral infections. Examples of such agents include, without limitation; polymerase inhibitors such as those disclosed in WO 2004/037818-A1, as well as those disclosed in WO 2004/037818 and WO 2006/045613; JTK-003, JTK-019, NM-283, HCV-796, R-803, R1728, R1626, as well as those disclosed in WO 2006/018725, WO 2004/074270, WO 2003/095441, US2005/0176701, WO 2006/020082, WO 2005/080388, WO 2004/064925, WO 2004/065367, WO 2003/007945, WO 02/04425, WO 2005/014543, WO 2003/000254, EP 1065213, WO 01/47883, WO 2002/057287, WO 2002/057245 and similar agents; replication inhibitors such as acyclovir, famciclovir, ganciclovir, cidofovir, lamivudine and similar agents; protease inhibitors such as the HIV protease inhibitors saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, fosamprenavir, brecanavir, atazanavir, tipranavir, palinavir, lasinavir, and the HCV protease inhibitors BILN2061, VX-950, SCH503034; and similar agents; nucleoside and nucleotide reverse transcriptase inhibitors such as zidovudine, didanosine, lamivudine, zalcitabine, abacavir, stavidine, adefovir, adefovir dipivoxil, fozivudine, todoxil, emtricitabine, alovudine, amdoxovir, elvucitabine, and similar agents; non-nucleoside reverse transcriptase inhibitors (including an agent having anti-oxidation activity such as immunocal, oltipraz etc.) such as nevirapine, delavirdine, efavirenz, loviride, immunocal, oltipraz, capravirine, TMC-278, TMC-125, etravirine, and similar agents; entry inhibitors such as enfuvirtide (T-20), T-1249, PRO-542, PRO-140, TNX-355, BMS-806, 5-Helix and similar agents; integrase inhibitors such as L-870,180 and similar agents; budding inhibitors such as PA-344 and PA-457, and similar agents; chemokine receptor inhibitors such as vicriviroc (Sch-C), Sch-D, TAK779, maraviroc (UK-427,857), TAK449, as well as those disclosed in WO 02/74769, WO 2004/054974, WO 2004/055012, WO 2004/055010, WO 2004/055016, WO 2004/055011, and WO 2004/054581, and similar agents; neuraminidase inhibitors such as CS-8958, zanamivir, oseltamivir, peramivir and similar agents; ion channel blockers such as amantadine or rimantadine and similar agents; and interfering RNA and antisense oligonucleotides and such as ISIS-14803 and similar agents; antiviral agents of undetermined mechanism of action, for example those disclosed in WO 2005/105761, WO 2003/085375, WO 2006/122011, ribavirin, and similar agents. The compounds of formula (I) and pharmaceutically acceptable salts thereof may also be used in combination with one or more other agents which may be useful in the prevention or treatment of viral infections for example immune therapies (e.g. interferon or other cytokines/chemokines, cytokine/chemokine receptor modulators, cytokine agonists or antagonists and similar agents); and therapeutic vaccines, antifibrotic agents, anti-inflammatory agents such as corticosteroids or NSAIDs (non-steroidal anti-inflammatory agents) and similar agents.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease for use in therapy.

In a further aspect there is provided a combination comprising a compound of formula (I) or pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease, for use in the treatment of infectious disease

In a further aspect there is provided the use of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease in the manufacture of a medicament for the treatment of infectious disease

In a further aspect there is provided a method of treating infectious disease comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease

In a further aspect there is provided a pharmaceutical composition comprising a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent useful in the treatment of infectious disease and one or more of pharmaceutically acceptable excipients.

There is also therefore provided a vaccine adjuvant comprising a compound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided an immugenic composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided a vaccine composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided a method of treating or preventing disease comprising the administration to a human subject suffering from or susceptible to disease, an immugenic composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided a method of treating or preventing disease comprising the administration to a human subject suffering from or susceptible to disease, a vaccine composition comprising an antigen or antigen composition and a compound of formula (I), or a pharmaceutically acceptable salt thereof.

There is further provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of an immugenic composition comprising an antigen or antigen composition, for the treatment or prevention of disease.

There is further provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, for the manufacture of a vaccine composition comprising an antigen or antigen composition, for the treatment or prevention of disease.

Compounds of formula (I) may be prepared by methods known in the art of organic synthesis as set forth in the schemes below and/or the specific Examples described below. In all of the methods, it is well understood that protecting groups for sensitive or reactive groups may be employed where necessary in accordance with general principles of chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (T. W. Green and P. G. M. Wuts (1999) Protective Groups in Organic Synthesis, 3^(rd) edition, John Wiley & Sons). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection of processes as well as the reaction conditions and order of their execution shall be consistent with the preparation of compounds of Formula (I).

Compound Preparation

The compounds of formula (I) and salts thereof may be prepared by the methodology described hereinafter, constituting further aspects of this invention.

Accordingly, there is provided a process for the preparation of a compound of formula (I), in which R₅ and R₆ are both OH which process comprises the deprotection of a compound of formula (II):

wherein R₁, R₂, R₃, R₄, Y₁ and Y₂ are as defined hereinbefore for a compound of formula (I), R₁₁ and R₁₂ are suitable protecting groups, such as, tert-butyldimethylsilyloxy (OTBDMS) and thereafter, if required, preparing a salt of the compound so-formed. A similar process would be used to prepare compounds of formula (I) in which either R₅ and R₆ is fluorine in which case only either R₁₁ or R₁₂ would be a suitably protected hydroxyl group such as tert-butyldimethylsilyloxy (OTBDMS)

For example, a compound of formula (II) is dissolved in a suitable solvent, for example pyridine, and heated at a suitable temperature, for example 50-55° C., then treated with a mixture of triethylamine trihydrofluoride and triethylamine, for a suitable period of time, for example 2-3 hours. The product (II) is isolated by precipitation by the addition of a solvent, for example acetone, and purification if required.

A compound of formula (II) may be prepared by deprotection of a compound of formula (III):

wherein, Y₁, Y₂, R₁₁, and R₁₂ are as defined hereinbefore for a compound of formula (II) and R₇, R₈, R₉, and R₁₀ are defined as when R₇═OH and R₈=NHCOiPr or R₇=NHBz and R₈═H

R₉═OH and R₁₀=NHCOiPr or R₉=NHBz and R₁₀═H

For example, a compound of formula (III) is dissolved in a suitable mixture, for example, methylamine in methanol or aqueous ammonia in methanol, and heated at a suitable temperature, for example 50-55° C., for a suitable period of time, for example 2-24 hours. The product (II) is isolated by removal of the solvent and purification if required.

A compound of formula (III) may be prepared by reaction of a compound of formula (IV):

. . . should be:—

wherein, Y₁, Y₂, R₇, R₈, R₉, R₁₀, R₁₁ and R₁₂ are defined as defined hereinbefore for a compound of formula (III).

For example, a compound of formula (IV) is dissolved in a suitable solvent, for example, pyridine, and treated with a suitable coupling reagent, for example, 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide, and heated at a suitable temperature, for example 20° C., for a suitable period of time, for example 1-2 hours. Quenching of the reaction by addition of a suitable solvent, for example water, then after the addition of an oxidising agent, for example iodine, and stirring at a suitable temperature, for example 20° C., for a suitable period of time, for example 15 minutes. The product (III) is isolated by removal of the solvent and purification if required.

A compound of formula (IV) may be prepared by reaction of a compound of formula (V) with a compound of formula (VI):

wherein, Y₁, Y₂, R₇, R₈ R₉, R₁₀, R₁₁ and R₁₂ are defined hereinbefore for a compound of formula (III) and DMTr is a 4,4′dimethoxytrityl protecting group.

For example, a compound of formula (VI) is dissolved in a suitable solvent, for example, acetonitrile in the presence of molecular sieves, and is treated with a solution of a compound of formula (V) dissolved in a suitable solvent, for example acetonitrile, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 1-2 hours. A solution of a suitable oxidising agent, for example a solution of tert-butyl hydroperoxide in decane, is added and the mixture stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 0.5 hours. After the quenching of the excess oxidising agent, for example by the addition of aqueous sodium bisulfite solution, and evaporation of the solvent the residue is dissolved in a suitable solvent, for example a mixture of dichloromethane and water, and treated with a suitable reagent, for example dichloroacetic acid, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 15-30 minutes. A solution containing the product (IV) is obtained by the addition of a suitable solvent, for example pyridine, and concentration by evaporation.

A compound of formula (V) may be prepared by reaction of a compound of formula (VII).

wherein, Y₁, R₉ and R₁₀ are defined as defined hereinbefore for a compound of formula (III) and DMTr is a 4,4′dimethoxytrityl protecting group.

For example, a compound of formula (VII) is dissolved in a suitable mixture, for example, acetonitrile containing water, is treated with pyridinium trifluoroacetate, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 1 minute then tert-butylamine is added and the mixture stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 10 minutes. The product is isolated by evaporation of the solvent then dissolved in a suitable solvent, for example dichloromethane containing water, and treated with dichloroacetic acid and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 10 minutes. A concentrated solution of the product (V) in acetonitrile is obtained by the addition of pyridine followed by azetroping the mixture with acetonitrile.

A compound of formula (VI) may be prepared by reaction of a compound of formula (VIII)

wherein, Y₂, R₇, R₈ and R₁₂ are defined as defined hereinbefore for a compound of formula (III). and DMTr is a 4,4′dimethoxytrityl protecting group.

For example, after azetroping with a suitable solvent, for example acetontrile, a compound of formula (VIII) is dissolved in a suitable solvent, for example, dichloromethane, and reacted with phosphitylating reagent, for example 3-((bis(diisopropylamino)phosphino)oxy)propanenitrile, in the presence of a base, for example 1H-tetrazole, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 20 hours. The product (VI) is isolated after an aqueous work-up and purification.

A compound of formula (VII) may be prepared by reaction of a compound of formula (IX)

wherein, wherein Y₁, R₉, R₁₀ and R₁₁ are defined as defined hereinbefore for a compound of formula (III) and DMTr is a 4,4′dimethoxytrityl protecting group.

For example, after azetroping with a suitable solvent, for example acetontrile, a compound of formula (IX) is dissolved in a suitable solvent, for example, dichloromethane, and reacted with phosphitylating reagent, for example 3-((bis(diisopropylamino)phosphino)oxy)propanenitrile, in the presence of a base, for example 1H-tetrazole, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 20 hours. The product (VII) is isolated after an aqueous work-up and purification.

A compound of formula (VIII) and a compound of formula (IX) may be prepared by reaction of a compound of formula (X)

wherein, Y is Y₁ or Y₂ and Z₁ is R₇ or R₉ and Z₂ is R₈ or R₁₀ as defined hereinbefore for a compound of formula (III) and DMTr is a 4,4′dimethoxytrityl protecting group.

For example a compound of formula (X) is dissolved in a suitable solvent, for example, pyridine, and reacted with a silylating reagent, for example tert-butyldimethylsilyl chloride, in the presence of a base, for example imidazole, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 4-20 hours. The products (VIII) and (IX) are isolated after an aqueous work-up and separation by chromatography.

A compound of formula (X) may be prepared by reaction of a compound of formula (XI)

wherein Y, Z₁ and Z₂ are defined hereinbefore for a compound of formula (X).

For example a compound of formula (XI) is dissolved in a suitable solvent, for example, pyridine, and reacted with 4,4′-dimethoxytrityl chloride, and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 4-20 hours. The product (X) is isolated after an aqueous work-up and purification if required.

Compounds of formula (XI) may be prepared by reaction of a compound of formula (XII) or formula (XIII)

wherein Y is as defined hereinbefore for a compound of formula (XI).

For example a compound of formula (XII) is dissolved in a suitable solvent, for example, pyridine, and reacted with trimethylsilylchloride and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 2 hours. After cooling to 0° C. benzoyl chloride is added. The mixture is stirred at a suitable temperature, for example 0-20° C., for a suitable period of time, for example 18-20 hours then treated with water followed by aqueous base, for example 0.88 ammonia solution. The product (XI) Z₁=NHBz and Z₂═H is isolated by evaporation of the solvent and washing with water.

For example a compound of formula (XIII) is dissolved in a suitable solvent, for example, pyridine, and reacted with trimethylsilylchloride and stirred at a suitable temperature, for example 20° C., for a suitable period of time, for example 2-4 hours. After cooling to 0° C. isobutyryl chloride is added. The mixture is stirred at a suitable temperature, for example 0-20° C., for a suitable period of time, for example 1-20 hours then cooled to a suitable temperature for example 0° C., treated with water followed by aqueous base, for example 0.88 ammonia solution. The product (XI) Z₁═OH and Z₂=NHCOiPr is isolated by evaporation of the solvent followed by an aqueous work-up and purification if required.

Aspects of the invention are illustrated by reference to, but are in no way limited by, the following Examples.

Analytical Methodology

¹H NMR

¹H NMR spectra were recorded in either CDCl₃, DMSO-d₆, CD₃CN or D₂O on either a Bruker DPX 400 or Bruker Avance DRX, Varian Unity 400 spectrometer or JEOL Delta all working at 400 MHz. The internal standard used was either tetramethylsilane or the residual protonated solvent at 7.25 ppm for CDCl₃ or 2.50 ppm for DMSO-d₆.

LCMS

System A

Column: 50 mm×2.1 mm ID, 1.7 m Acquity UPLC BEH C₁₈

Flow Rate: 1 mL/min.

Temp: 40° C.

UV detection range: 210 to 350 nm

Mass spectrum: Recorded on a mass spectrometer using alternative-scan positive and negative mode electrospray ionisation

Solvents: A: 0.1% v/v formic acid in water

-   -   B: 0.1% v/v formic acid acetonitrile

Gradient: Time (min.) A % B % 0 97 3 1.5 0 100 1.9 0 100 2.0 97 3 System B Column: 50 mm×2.1 mm ID, 1.7 μm Acquity UPLC BEH C₁₈ Flow Rate: 1 mL/min. Temp: 40° C. UV detection range: 210 to 350 nm Mass spectrum: Recorded on a mass spectrometer using alternative-scan positive and negative mode electrospray ionisation

-   Solvents: A: 10 mM ammonium bicarbonate in water adjusted to pH10     with ammonia solution     -   B: acetonitrile

Gradient: Time (min.) A % B % 0 99 1 1.5 3 97 1.9 3 97 2.0 0 100 System C Column: 50 mm×2.1 mm ID, 1.7 μm Acquity UPLC CSH C₁₈ Flow Rate: 1 mL/min. Temp: 40° C. Injection volume 0.5

L UV detection range: 210 to 350 nm Mass spectrum: Recorded on a mass spectrometer using alternative-scan positive and negative mode electrospray ionisation Solvents: A: 0.1% v/v formic acid in water

-   -   B: 0.1% v/v formic acid acetonitrile

Gradient: Time (min.) A % B % 0 97 3 1.5 5 95 1.9 5 95 2.0 97 3 System D Column: 50 mm×2.1 mm ID, 1.7 μm Acquity UPLC CSH C₁₈ Flow Rate: 1 mL/min. Temp: 40° C. Injection volume 0.3

L UV detection range: 210 to 350 nm Mass spectrum: Recorded on a mass spectrometer using alternative-scan positive and negative mode electrospray ionisation

-   Solvents: A: 10 mM ammonium bicarbonate in water adjusted to pH10     with ammonia solution     -   B: acetonitrile

Gradient: Time (min.) A % B % 0 97 3 0.05 97 3 1.5 5 95 1.9 5 95 2.0 97 3 System E Column: 50 mm×2.1 mm ID, 1.7 m Acquity UPLC BEH C₁₈ Flow Rate: 1 mL/min. Temp: 40° C. UV detection range: 210 to 350 nm Mass spectrum: Recorded on a mass spectrometer using alternative-scan positive and negative mode electrospray ionisation

-   Solvents: A: 10 mM ammonium bicarbonate in water adjusted to pH10     with ammonia solution     -   B: acetonitrile

Gradient: Time (min.) A % B % 0 99 1 1.5 3 97 1.9 3 97 2.0 99 1 Mass Directed Autopreparative HPLC (MDAP)

Mass directed autopreparative HPLC was undertaken under the conditions given below. The UV detection was an averaged signal from wavelength of 210 nm to 350 nm and mass spectra were recorded on a mass spectrometer using alternate-scan positive and negative mode electrospray ionization.

Method A

Method A was conducted on a Sunfire C₁₈ column (typically 150 mm×30 mm i.d. 5 μm packing diameter) at ambient temperature. The solvents employed were:

A=0.1% v/v solution of formic acid in water

B=0.1% v/v solution of formic acid in acetonitrile.

Method B

Method B was conducted on an XBridge C₁₈ column (typically 100 mm×30 mm i.d. 5 μm packing diameter) at ambient temperature. The solvents employed were:

A=10 mM aqueous ammonium bicarbonate adjusted to pH 10 with ammonia solution.

B=acetonitrile.

Method C

Method C was conducted on a Sunfire C₁₈ column (typically 150 mm×30 mm i.d. 5 μm packing diameter) at ambient temperature. The solvents employed were:

A=0.1% v/v solution of trifluoroacetic acid in water

B=0.1% v/v solution of trifluoroacetic acid in acetonitrile.

Abbreviations

The following list provides definitions of certain abbreviations as used herein. It will be appreciated that the list is not exhaustive, but the meaning of those abbreviations not herein below defined will be readily apparent to those skilled in the art.

DCM Dichloromethane

DMF N, N-Dimethylformamide

DMSO Dimethylsulphoxide

DMTr Dimethoxytrityl

THF Tetrahydrofuran

EtOAc Ethyl acetate

MeOH Methanol

EtOH Ethanol

MeCN Acetonitrile

HCl Hydrochloric acid

HPLC High performance liquid chromatography

MDAP Mass Directed Autopreparative HPLC

SPE Solid phase extraction

MeOH Methanol

TBDMS tert-Butyldimethylsilyl

TBME tert-Butyl methy ether

TFA Trifluoroacetic acid

DIPEA N, N-Diisopropylethylamine

Nomenclature

The compounds were named from the structure using either the nomenclature tool in Chem Draw (CambridgeSoft) or Marvin Sketch (ChemAxon).

Reaction Intermediates Intermediate 1: N-(9-((1R,2S,3R,4R)-2,3-Dihydroxy-4-(hydroxymethyl)cyclopentyl)-9H-purin-6-yl)benzamide

Chlorotrimethylsilane (17.94 mL, 141 mmol) was added to a suspension of (1R, 2S, 3R, 5R)-3-(6-amino-9H-purin-9-yl)-5-(hydroxymethyl)cyclopentane-1,2-diol (5.00 g, 18.85 mmol) (Yang Y. et al, J. Org. Chem., 2004: 69, 3993-3996) in anhydrous pyridine (80 mL) under a nitrogen atmosphere. The reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was cooled to 0° C. in an ice/water bath and benzoyl chloride (3.72 mL, 32.0 mmol) was added dropwise over 3 minutes. The mixture was allowed to warm to room temperature and was stirred under a nitrogen atmosphere for 19.5 hours. The reaction mixture was cooled to 0° C. in an ice/water bath, quenched with water (15 mL) and stirred at 0° C. for 5 minutes. After allowing the mixture to warm to room temperature, 0.88 ammonia solution (39.5 mL, 714 mmol) was added and the mixture was stirred at room temperature for 20 minutes. The reaction mixture was evaporated in-vacuo to yield a white solid. Cold water (100 mL) was added to the solid and the suspension was filtered. The solid was washed with cold water (3×25 mL) and ether (3×25 mL). A small sample of the solid was dried in the drying pistol for 1 hour and analysed by ¹H NMR. The remaining solid was dried in the drying pistol for 16 hours to yield the title compound as a white solid (5.977 g).

LCMS (System E): t_(RET)=0.52 min; MH⁺ 370

Intermediate 2: N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2,3-dihydroxycyclopentyl)-9H-purin-6-yl)benzamide

N-(9-((1R,2S,3R,4R)-2,3-Dihydroxy-4-(hydroxymethyl)cyclopentyl)-9H-purin-6-yl)benzamide was azeotroped three times with anhydrous pyridine (3×20 mL). A solution of 4,4′-dimethoxytrityl chloride (1.11 g, 3.28 mmol) in anhydrous pyridine (6 mL) was added dropwise to a suspension of N-(9-((1R,2S,3R,4R)-2,3-dihydroxy-4-(hydroxymethyl)cyclopentyl)-9H-purin-6-yl)benzamide (1.164 g, 3.15 mmol) in anhydrous pyridine (19 mL). The reaction mixture was stirred at room temperature for 3.5 hours.

The reaction mixture was evaporated in-vacuo and the resulting oil was partitioned between ethyl acetate (100 mL) and saturated aqueous sodium hydrogen carbonate solution (100 mL). The organic layer was separated and the aqueous layer was extracted with additional ethyl acetate (100 mL). The combined organic extracts were washed with brine (50 mL), dried using a hydrophobic frit and evaporated in-vacuo to yield a white solid (2.058 g). The solid was dissolved in the minimum volume of dichloromethane, loaded onto a 100 g dichloromethane pre-conditioned silica cartridge and purified using a 0-5% methanol in dichloromethane gradient over 60 minutes (detection wavelength=240 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (1.475 g).

LCMS (System E): t_(RET)=1.18 min; MH⁺ 672

Intermediates 3a and 3b: N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-3-hydroxycyclopentyl)-9H-purin-6-yl)benzamide (3a) and N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3-((tert-butyldimethylsilyl)oxy)-2-hydroxycyclopentyl)-9H-purin-6-yl)benzamide (3b)

Imidazole (0.436 g, 6.40 mmol) and tert-butylchlorodimethylsilane (0.405 g, 2.69 mmol) were added to a stirred solution of N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2,3-dihydroxycyclopentyl)-9H-purin-6-yl)benzamide (1.433 g, 2.133 mmol) in anhydrous pyridine (5 mL) at room temperature. The reaction mixture was stirred under a nitrogen atmosphere for 3 hours. The reaction mixture was partitioned between dichloromethane (50 mL) and water (50 mL). The organic layer was separated and the aqueous extracted with dichloromethane (50 mL). The combined organic extracts were washed with brine (50 mL), dried using a hydrophobic frit and evaporated in-vacuo to yield a colourless oil. The oil was azeotroped with toluene (2×30 ml) to afford a white solid (1.54 g). The solid was dissolved in DMSO (5 mL), applied to a preconditioned reversed-phase Biotage 120 g KP-C18-HS cartridge and eluted using 1 column volume of 50% acetonitrile in water followed by a 50-80% acetonitrile in water gradient over 20 column volumes (detection wavelength 230 nm).

Appropriate fractions were combined and evaporated in-vacuo to yield the title compound 3a as a white solid (477 mg) and the title compound 3b as a white solid (674 mg)

Intermediate 3a

LCMS (System A): t_(RET)=1.47 min; MH⁺ 786

Intermediate 3b

LCMS (System A): t_(RET)=1.56 min; MH⁺ 786

Intermediate 4: (1R,2S,3R,5R)-3-(6-Benzamido-9H-purin-9-yl)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)cycopentyl (2-cyanoethyl) diisopropylphosphoramidite

N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-3-hydroxycyclopentyl)-9H-purin-6-yl)benzamide (379 mg, 0.482 mmol) was azeotroped in anhydrous acetonitrile (2×10 mL). 3-((bis(diisopropylamino)phosphino)oxy)propanenitrile (0.191 ml, 0.603 mmol) and 1H-tetrazole (43 mg, 0.614 mmol) were added to a stirred solution of the azeotroped N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-3-hydroxycyclopentyl)-9H-purin-6-yl)benzamide (379 mg, 0.482 mmol) in anhydrous dichloromethane (5.5 mL) at room temperature. The reaction mixture was stirred under a nitrogen atmosphere for 20 hours.

3-((bis(Diisopropylamino)phosphino)oxy)propanenitrile (0.031 ml, 0.096 mmol) and 1H-tetrazole (7 mg, 0.100 mmol) were added and the reaction mixture was stirred under nitrogen for a further 4 hours. The reaction mixture was diluted with dichloromethane (50 mL) and washed with saturated aqueous sodium hydrogen carbonate solution (50 mL). The organic layer was separated and the aqueous extracted with further dichloromethane (50 mL). The combined organic extracts were dried using a hydrophobic frit and evaporated in-vacuo to yield a colourless glass (577 mg). A 20 g silica cartridge was pre-conditioned using 1% triethylamine in dichloromethane (140 mL), dichloromethane (140 mL), ethyl acetate (140 mL) and cyclohexane (140 mL). The colourless glass was loaded in the minimum volume of dichloromethane and eluted using a 0-100% ethyl acetate in cyclohexane gradient over 60 minutes (detection wavelength=254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white foam (292 mg).

LCMS (System E): t_(RET)=1.70 min; MH⁺ 986

Intermediate 5: (1R,2S,3R,5R)-3-(6-Benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)cyclopentyl hydrogen phosphonate

To a solution of (1R,2S,3R,5R)-3-(6-benzamido-9H-purin-9-yl)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite (285 mg, 0.289 mmol) in acetonitrile (1.5 mL) and water (0.011 mL, 0.611 mmol) at room temperature was added pyridinium trifluoroacetate (67 mg, 0.347 mmol). The reaction mixture was stirred at room temperature for 1 minute. tert-Butylamine (1.442 mL, 13.73 mmol) was added and the reaction mixture was stirred at room temperature for 10 minutes. The reaction mixture was evaporated in-vacuo (water bath at 35° C.) to yield a white foam which was dissolved in acetonitrile (3 mL) and evaporated in-vacuo to yield a white foam. The foam was again dissolved in acetonitrile (3 mL) and evaporated in-vacuo to yield a white foam. The foam was dissolved in dichloromethane (6.85 ml) and water (0.052 mL, 2.89 mmol). Dichloroacetic acid (0.21 mL, 2.54 mmol) was added and the red solution was stirred at room temperature for 10 minutes. Analysis of the reaction mixture by LCMS confirmed the presence of the title compound.

LCMS (System E): t_(RET)=0.73 min; MH⁺ 548

The reaction mixture was quenched with pyridine (0.411 mL, 5.09 mmol) and concentrated in-vacuo to approximately 2 mL volume (water bath at 35-40° C.). The resulting white suspension was azeotroped with anhydrous acetonitrile (3×3 mL) (water bath at 35-40° C.), concentrating to approximately 2 mL volume on the first and second azeotropes and approximately 1 mL volume on the final azeotrope. The flask was stoppered with a suba-seal, evacuated/flushed with nitrogen and the white suspension used immediately in the next sequence of reactions.

Intermediate 6: N-(9-((1R,2S,3R,4R)-2,3-Dihydroxy-4-(hydroxymethyl)cyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide

Chlorotrimethylsilane (2.71 mL, 21.33 mmol) was added portionwise (5 portions) over 2 hours to a suspension of 2-amino-9-((1R,2S,3R,4R)-2,3-dihydroxy-4-(hydroxymethyl)cyclopentyl)-1H-purin-6(9H)-one (1.00 g, 3.56 mmol) (Exall A. M. et al, Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry, 1991: 2467-77) in anhydrous pyridine (25 mL) under a nitrogen atmosphere. The reaction was stirred at room temperature for a further 1.5 hours. The reaction was cooled to 0° C. in an ice/water bath and isobutyryl chloride (1.117 mL, 10.67 mmol) was added dropwise over 3 minutes. The mixture was allowed to warm to room temperature and stirred for 1 hour. The reaction mixture was cooled to 0° C. in an ice/water bath and quenched with water (15 mL). After stirring for 5 minutes at 0° C. the reaction was allowed to warm to room temperature. Ammonia (0.880, 7.40 mL, 134 mmol) was added to the mixture and stirred for 60 minutes. The reaction mixture was evaporated in vacuo to yield a brown solid. The brown solid was partitioned between water (100 mL) and dichloromethane (100 mL). The organic layer was back extracted with water (50 mL). The aqueous layers were combined and evaporated in vacuo to yield a brown solid. The brown solid was triturated with methanol (3×50 mL) and the liquid portion was decanted before being evaporated in vacuo to yield a dark brown solid (3.919 g). The dark brown solid was dissolved in DMSO (16 mL) and purified by chromatography using a 400 g reverse phase C-18 silica cartridge, eluting with 1 column volume of 5% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia followed by a gradient of 5-30% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia over 20 column volumes. Appropriate fractions were combined and evaporated in vacuo to yield the title compound as a white solid (1.022 g).

LCMS (System E): t_(RET)=0.46 min; MH⁺ 352

Intermediate 7: N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2,3-dihydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide

N-(9-((1R,2S,3R,4R)-2,3-Dihydroxy-4-(hydroxymethyl)cyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (1.025 g, 2.92 mmol) was azetroped twice with anhydrous pyridine (2×20 mL). A solution of 4,4′-dimethoxytrityl chloride (1.028 g, 3.03 mmol) in anhydrous pyridine (5.5 mL) was added dropwise over 5 minutes to a solution of the azeotroped N-(9-((1R,2S,3R,4R)-2,3-dihydroxy-4-(hydroxymethyl)cyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (1.025 g, 2.92 mmol) in anhydrous pyridine (17 mL) at room temperature. The reaction was stirred at room temperature for 90 minutes. An additional portion of 4,4′-dimethoxytrityl chloride (0.356 g, 1.051 mmol) in anhydrous pyridine (2 mL) was added to the reaction mixture and stirring continued for 1 hour. The reaction mixture was evaporated in-vacuo and the resulting oil was partitioned between ethyl acetate (100 mL) and saturated aqueous sodium hydrogen carbonate solution (100 mL). The organic layer was separated and washed with brine (30 mL), dried using a hydrophobic frit and evaporated in-vacuo to yield a yellow solid (2.4 g). The solid material was dissolved in the minimum volume of dichloromethane, loaded onto a 100 g dichloromethane pre-conditioned silica cartridge and purified by chromatography using 0-8% methanol in dichloromethane gradient over 25 column volumes (detection wavelength=240 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (1.3 g).

LCMS (System E): t_(RET)=1.13 min; MH⁺ 654

Intermediate 8a and 8b: N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-3-hydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (8a) and N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3-((tert-butyldimethylsilyl)oxy)-2-hydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (8b)

Imidazole (2.298 g, 33.8 mmol) and tert-butylchlorodimethylsilane (2.204 g, 14.63 mmol) were added to a stirred solution of N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2,3-dihydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (7.355 g, 11.25 mmol) in anhydrous pyridine (29 mL) at room temperature. The reaction mixture was stirred under a nitrogen atmosphere for 6 hours. The solution was partitioned between water (100 mL) and dichloromethane (100 mL). The organic layer was separated and the aqueous layer was back extracted with dichloromethane (100 mL). The combined organic extracts were dried using MgSO₄ and a hydrophobic frit before evaporating in vacuo to yield an off white foam (8.903 g). A portion of the foam (3.308 g) was dissolved in DMSO (12 mL), applied to a preconditioned reversed-phase Biotage 400 g KP-C18-HS cartridge and eluted using 1 column volume of 55% acetonitrile in water followed by a 55-75% acetonitrile in water gradient over 20 column volumes (detection wavelength 237 nm). Appropriate fractions were combined into two batches and evaporated in vacuo to yield the title compound 8a as a white solid (1.223 g) and title compound 8b as a white solid (1.268 g).

Intermediate 8a

LCMS (System C): t_(RET)=1.51 min; MH⁺ 768

Intermediate 8b

LCMS (System C): t_(RET)=1.59 min; MH⁺ 768

Mixed fractions were evaporated in vacuo and combined with the remainder of initial white foam (5.595 g). The material was dissolved in DMSO (15 mL), applied to a preconditioned reversed-phase Biotage 400 g KP-C18-HS cartridge and eluted using 1 column volume of 55% acetonitrile in water followed by a 55-75% acetonitrile in water gradient over 20 column volumes (detection wavelength 237 nm). Appropriate fractions were combined into two batches and evaporated in vacuo to yield an additional batch of the title compound 8a as a white solid (1.837 g) and an additional batch title compound 8b as a white solid (1.844 g)

Intermediate 9: (1S,2R,3R,5R)-3-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite

N-(9-((1R,2S,3R,4R)-4-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-3-((tert-butyldimethylsilyl)oxy)-2-hydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (455 mg, 0.592 mmol) was azeotroped in anhydrous acetonitrile (2×10 mL). 3-((bis(Diisopropylamino)phosphino)oxy)propanenitrile (0.226 mL, 0.711 mmol) and 1H-tetrazole (50 mg, 0.714 mmol) were added to a stirred solution of the azeotroped N-(9-((1R,2S,3R,4R)-4-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-3-((tert-butyldimethylsilyl)oxy)-2-hydroxycyclopentyl)-6-oxo-6,9-dihydro-1H-purin-2-yl)isobutyramide (455 mg, 0.592 mmol) in anhydrous dichloromethane (7 mL) at room temperature. The reaction mixture was stirred under a nitrogen atmosphere for 20 hours. The reaction mixture was diluted with dichloromethane (50 mL) and washed with saturated aqueous sodium hydrogen carbonate solution (50 mL). The organic layer was separated and the aqueous extracted with further dichloromethane (50 mL). The combined organic extracts were dried using a hydrophobic frit and evaporated in-vacuo to yield a white foam (640 mg). A 20 g silica cartridge was pre-conditioned using 1% triethylamine in dichloromethane (140 mL), dichloromethane (140 mL), ethyl acetate (140 mL) and cyclohexane (140 mL). The crude material was dissolved in the minimum volume of dichloromethane and then loaded onto the column and eluted using a 0-100% ethyl acetate in cyclohexane gradient over 40 minutes (detection wavelength=254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white foam (460 mg).

LCMS (System E): t_(RET)=1.69, 1.73 min; MH⁺ 968

Intermediate 10: (1R,2S,3R,5R)-3-(6-benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)cyclopentyl hydrogen phosphonate

(1S,2R,3R,5R)-3-((bis(4-Methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite (363 mg, 0.375 mmol) was dissolved in anhydrous acetonitrile (2.5 mL), three 3 Å molecular sieves were added and the solution was stored under a nitrogen atmosphere for approximately 45 minutes (note—a precipitate formed on standing which required slight warming in order to form a solution again). To a suspension of crude (1R,2S,3R,5R)-3-(6-Benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)cyclopentyl hydrogen phosphonate (theoretical mass of material: 158 mg, 0.289 mmol) in anhydrous acetonitrile (1 mL) at room temperature under a nitrogen atmosphere was added the solution of (1S,2R,3R,5R)-3-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite (363 mg, 0.375 mmol) in anhydrous acetonitrile (2.5 mL) dropwise over 30 seconds. The reaction mixture was stirred at room temperature for 50 minutes. Anhydrous tert-butyl hydroperoxide solution (5.5M in decane) (0.157 mL, 0.866 mmol) was added and the reaction mixture was stirred at room temperature for 30 minutes. A further portion of anhydrous tert-butyl hydroperoxide solution (5.5M in decane) (0.157 mL, 0.866 mmol) was added and the reaction mixture was stirred at room temperature for 1 hour. The reaction mixture was cooled in an ice/water bath and quenched with 33% aqueous sodium bisulfite solution (0.288 mL). The mixture was evaporated in-vacuo and the residual oil was stored in the fridge in a stoppered flask for 20 hours. The material was then dissolved in dichloromethane (9.2 mL) and water (0.052 mL, 2.89 mmol). Dichloroacetic acid (0.276 mL, 3.35 mmol) was added and the pale orange solution was stirred at room temperature for 15 minutes.

The reaction mixture was quenched with anhydrous pyridine (3 mL) and concentrated in-vacuo (water bath at 35-40° C.) to approximately 3 mL volume. Further anhydrous pyridine (7.5 mL) was added and the reaction mixture again concentrated in-vacuo (water bath at 35-40° C.) to approximately 3 mL volume which was stored in the fridge in a stoppered flask for 16 hours. The crude mixture containing the title compound was used in the next sequence of reactions.

LCMS (System B): t_(RET)=0.96-0.98 min; MH⁺ 1128

Intermediate 11: N-{9-[(1S,6R,8R,9S,10R,15R,17R,18R)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide

To crude (1R,2S,3R,5R)-3-(6-benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)cyclopentyl hydrogen phosphonate (theoretical mass of desired material in crude mixture: 326 mg, 0.289 mmol) in anhydrous pyridine (3 mL total volume of pyridine and crude material) was added further anhydrous pyridine (6 mL). 2-Chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (187 mg, 1.011 mmol) was added and the reaction mixture was stirred at room temperature for 15 minutes. A further aliquot of 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (100 mg, 0.542 mmol) was added to the reaction mixture and stirring continued for 40 minutes. The reaction was quenched with water (0.28 mL, 15.54 mmol) and iodine (95 mg, 0.376 mmol) was added immediately. The reaction mixture was stirred at room temperature for 15 minutes and then poured onto 0.14% aqueous sodium bisulfite solution (41 mL). After 5 minutes, solid sodium hydrogen carbonate (1.17 g) was added portionwise (CARE: gas evolution) and the mixture was extracted with ethyl acetate/diethylether (1:1). The organic layer was separated and the aqueous back-extracted with ethyl acetate/diethylether (1:1). The combined organic layers were passed through a hydrophobic frit and evaporated in-vacuo to yield a dark yellow oil (1.206 g). The crude material was dissolved in the minimum volume of dichloromethane, applied to a dichloromethane preconditioned 100 g silica cartridge and eluted using 0-25% methanol in dichloromethane gradient over 22 column volumes (detection wavelength 260 nm).

Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a pale yellow solid (143 mg).

LCMS (System B): t_(RET)=1.00-1.07 min; MH⁺ 1127

Intermediate 12: N-{9-[(1S,6R,8R,9S,10R,15R,17R,18R)-17-(2-amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-3,12-dioxo-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide

Methylamine (33 wt. % in absolute ethanol) (3.35 mL, 26.9 mmol) was added to N-{9-[(1S,6R,8R,9S,10R,15R,17R,18R)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide (143 mg, 0.127 mmol). The solution was stirred at room temperature for 2 hours. A further 3.35 mL (26.9 mmol) of methylamine (33 wt. % in absolute ethanol) was added and the solution was stirred at room temperature for a further 19 hours. The deprotection was progressing no further in methylamine (33 wt. % in absolute ethanol) at room temperature and the reaction mixture was evaporated in-vacuo and to the remaining residue was added ammonia solution (0.88) (11 mL) and methanol (4 mL). The suspension was stirred at 50° C. for 22 hours in a sealed vessel and then at 55° C. for 4 hours in a sealed vessel (microwave vial). The reaction mixture was evaporated in-vacuo and the remaining residue was suspended in ammonia solution (0.88) (6 mL) and methanol (2 mL). The suspension was stirred at 55° C. for 18 hours in a sealed vessel then the reaction mixture was evaporated in-vacuo to yield a pale yellow solid.

The solid was dissolved in the minimum volume of DMSO, applied to a preconditioned reversed-phase Biotage 120 g KP-C18-HS cartridge and eluted using a 15-40% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 18 column volumes (detection wavelength 254 nm).

Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (29 mg).

LCMS (System B): t_(RET)=0.71 min; MH⁺ 899

Intermediate 13: (1R,2S,3R,5R)-3-(6-Benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-((((((2R,3R,4R,5R)-4-((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)-2-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)tetrahydrofuran-3-yl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)cyclopentyl hydrogen phosphonate

Prepared similarly to Intermediate 10 from (2R,3R,4R,5R)-5-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-4-((tert-butyldimethylsilyl)oxy)-2-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)tetrahydrofuran-3-yl (2-cyanoethyl) diisopropylphosphoramidite (950 mg, 0.979 mmol) and crude (1R,2S,3R,5R)-3-(6-benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)cyclopentyl hydrogen phosphonate (413 mg, 0.755 mmol). The crude title compound was obtained as a solution in anhydrous pyridine (8 mL) which was used directly in the next reaction.

LCMS (System D): t_(RET)=1.01 min; MH⁺ 1131

Intermediate 14: N-{9-[(1R,6R,8R,9S,10R,15R,17R,18R)-9,18-bis[(tert-Butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide

To crude (1R,2S,3R,5R)-3-(6-benzamido-9H-purin-9-yl)-2-((tert-butyldimethylsilyl)oxy)-5-((((((2R,3R,4R,5R)-4-((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)-2-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)tetrahydrofuran-3-yl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)cyclopentyl hydrogen phosphonate (theoretical mass of desired material in crude mixture: 853 mg, 0.755 mmol) in anhydrous pyridine (8 mL) was added further anhydrous pyridine (15 mL). 2-Chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (488 mg, 2.64 mmol) was added and the reaction mixture was stirred under nitrogen at room temperature for 45 minutes. More 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (488 mg, 2.64 mmol) was added and the reaction mixture was stirred under nitrogen at room temperature for a further 45 minutes. More 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (139 mg, 0.755 mmol) was then added and the reaction mixture was stirred under nitrogen at room temperature for a further 45 minutes when the reaction was quenched with water (1.086 mL, 60.35 mmol, 10 eq relative to DMOCP) and iodine (249 mg, 0.982 mmol) was added immediately. The reaction mixture was stirred at room temperature for 5 minutes and then poured onto 0.14% aqueous sodium bisulfite solution (110 mL). After 5 min, solid sodium hydrogen carbonate (3.058 g) was added portionwise and the mixture was extracted with ethyl acetate:diethylether (1:1) (125 mL). The organic layer was separated and the aqueous layer back-extracted with ethyl acetate:diethylether (1:1) (125 mL). The combined organic layers were passed through a hydrophobic frit and evaporated in-vacuo to yield an orange oil (2.26 g). A portion of this crude product (1.06 g) was dissolved in the minimum volume of dichloromethane, applied to a dichloromethane preconditioned 100 g silica cartridge and eluted using a 0-25% methanol in dichloromethane gradient over 20 column volumes (detection wavelength 280 nm). Appropriate fractions were combined and evaporated in-vacuo to yield a white solid (200 mg). The remainder of the crude product (1.20 g) was dissolved in the minimum volume of dichloromethane and purified in the same way to yield a white solid (270 mg). The two batches of white solid were combined to give the crude title compound (470 mg).

LCMS (System D): t_(RET)=1.06-1.08 min; MH⁺ 1129

This material was used directly in the next reaction

Intermediate 15: (1R,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione

To a solution of crude N-{9-[(1R,6R,8R,9S,10R,15R,17R,18R)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide (470 mg, 0.417 mmol) in methanol (8 mL) was added 0.88 ammonia solution (8 mL). The suspension was stirred at 55° C. for 64 hours in a sealed microwave vial. The cooled reaction mixture was evaporated in-vacuo (methanol added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid (478 mg) which was dissolved in the minimum volume of DMSO, applied to a preconditioned reversed-phase Biotage 120 g KP-C18-HS cartridge and eluted using a 15-40% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 18 column volumes (detection wavelength 254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (163 mg).

LCMS (System D): t_(RET)=0.73 min; MH⁺ 901

Intermediate 16: (2R,3R,4R,5R)-5-(6-Benzamido-9H-purin-9-yl)-4-((tert-butyldimethylsilyl)oxy)-2-(hydroxymethyl)tetrahydrofuran-3-yl hydrogen phosphonate

Prepared similarly to Intermediate 5 from (2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-2-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-4-((tert-butyldimethylsilyl)oxy)tetrahydrofuran-3-yl (2-cyanoethyl) diisopropylphosphoramidite (628 mg, 0.636 mmol) to give a suspension of the title compound in anhydrous acetonitrile (ca 2 mL)

LCMS (System E): t_(RET)=0.74 min; MH⁺ 550

Intermediate 17: (2R,3R,4R,5R)-5-(6-Benzamido-9H-purin-9-yl)-4-((tert-butyldimethylsilyl)oxy)-2-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)tetrahydrofuran-3-yl hydrogen phosphonate

Prepared similarly to Intermediate 10 from (1S,2R,3R,5R)-3-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite (801 mg, 0.827 mmol) and crude (2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-4-((tert-butyldimethylsilyl)oxy)-2-(hydroxymethyl)tetrahydrofuran-3-yl hydrogen phosphonate (theoretical mass of material: 350 mg, 0.636 mmol). The crude title compound was obtained as a solution in anhydrous pyridine (6 mL) which was used directly in the next reaction.

LCMS (System B): t_(RET)=1.00 min; MH⁺ 1130

Intermediate 18: N-{9-[(1S,6R,8R,9R,10R,15R,17R,18R)-9,18-bis[(tert-Butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide

Prepared similarly to Intermediate 14 by treatment of crude (2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-4-((tert-butyldimethylsilyl)oxy)-2-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)tetrahydrofuran-3-yl hydrogen phosphonate (theoretical mass of desired material in crude mixture: 0.719 g, 0.636 mmol) with 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (2×411 mg, 2.226 mmol and 1×116 mg, 0.635 mmole) and quenching with water (0.915 mL) and iodine (210 mg, 0.827 mmol) to give, after work up and chromatographic purification the crude title compound as a pale yellow solid (290 mg).

LCMS (System B): t_(RET)=1.06, 1.08 min; MH⁺ 1128

This material was used directly in the next reaction

Intermediate 19: (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione

To a solution of crude N-{9-[(1S,6R,8R,9R,10R,15R,17R,18R)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide (290 mg, 0.257 mmol) in methanol (7 mL) was added 0.88 ammonia solution (7 mL). The suspension was stirred at 55° C. for 94 hours in a sealed microwave vial and then cooled and evaporated in-vacuo (methanol was added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid. This solid was dissolved in methanol (9 mL) and 0.88 ammonia solution (9 mL) was added. The resulting suspension was stirred at 55° C. for 22 hours in a sealed microwave vial and then cooled and evaporated in-vacuo (methanol was added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid (260 mg). This material was dissolved in the minimum volume of DMSO, applied to a preconditioned reversed-phase Biotage 120 g KP-C18-HS cartridge and eluted using a 15-40% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 17 column volumes (detection wavelength 254 nm). Appropriate fractions were combined and evaporated in-vacuo (acetonitrile added to the fractions to reduce foaming during evaporation) to yield the crude title compound as a white solid (71 mg).

LCMS (System B): t_(RET)=0.77 min; MH⁺ 901

Intermediate 20: (2R,3R,4R,5R)-5-(6-Benzamido-9H-purin-9-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-yl hydrogen phosphonate

Prepared similarly to Intermediate 5 from (2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-2-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-4-fluorotetrahydrofuran-3-yl (2-cyanoethyl) diisopropylphosphoramidite (453 mg, 0.517 mmol) to give a suspension of the crude title compound in anhydrous acetonitrile (ca 2 mL)

LCMS (System E): t_(RET)=0.50 min; MH⁺ 438

Intermediate 21: (2R,3R,4R,5R)-5-(6-Benzamido-9H-purin-9-yl)-2-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)-4-fluorotetrahydrofuran-3-yl hydrogen phosphonate

Prepared similarly to Intermediate 10 from (1S,2R,3R,5R)-3-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)-2-((tert-butyldimethylsilyl)oxy)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl (2-cyanoethyl) diisopropylphosphoramidite (651 mg, 0.672 mmol) and crude ((2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-4-fluoro-2-(hydroxymethyl)tetrahydrofuran-3-yl hydrogen phosphonate (theoretical mass of material: 226 mg, 0.517 mmol). The crude title compound was obtained as a solution in anhydrous pyridine (5 mL) which was used directly in the next reaction.

LCMS (System B): t_(RET)=0.89 min; MH⁺ 1018

Intermediate 22: N-{9-[(1S,6R,8R,9R,10R,15R,17R,18R)-18-[(tert-Butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-9-fluoro-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide

Prepared similarly to Intermediate 14 by treatment of crude (2R,3R,4R,5R)-5-(6-benzamido-9H-purin-9-yl)-2-((((((1S,2R,3R,5R)-2-((tert-butyldimethylsilyl)oxy)-3-(hydroxymethyl)-5-(2-isobutyramido-6-oxo-1H-purin-9(6H)-yl)cyclopentyl)oxy)(2-cyanoethoxy)phosphoryl)oxy)methyl)-4-fluorotetrahydrofuran-3-yl hydrogen phosphonate (theoretical mass of desired material in crude mixture: 0.526 g, 0.517 mmol) with 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphorinane 2-oxide (2×334 mg, 1.810 mmol, 1×95 mg, 0.517 mmol) and quenching with water (0.744 mL) and iodine (171 mg) to give, after work up and chromatographic purification the crude title compound as a pale yellow solid (175 mg).

LCMS (System B): t_(RET)=0.84 min; MH⁺ 1016

This material was used directly in the next reaction

Intermediate 23: (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-18-[(tert-butyldimethylsilyl)oxy]-9-fluoro-3,12-dihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione

To a solution of crude N-{9-[(1S,6R,8R,9R,10R,15R,17R,18R)-18-[(tert-butyldimethylsilyl)oxy]-3-(2-cyanoethoxy)-9-fluoro-12-hydroxy-17-[2-(2-methylpropanamido)-6-oxo-6,9-dihydro-1H-purin-9-yl]-3,12-dioxo-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecan-8-yl]-9H-purin-6-yl}benzamide (175 mg, 0.172 mmol) in methanol (6 mL) was added 0.88 ammonia solution (5 mL). The suspension was stirred at 50° C. for 23 hours in a sealed microwave vial. 0.88 Ammonia solution (2 mL) was added and the reaction mixture was stirred at 50° C. for a further 24 hours and then cooled and evaporated in-vacuo (methanol added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid (185 mg). This material was dissolved in methanol (10 mL) and 0.88 ammonia solution (7 mL) was added and the suspension was stirred at 50° C. for 20 hours in a sealed microwave vial. The cooled reaction mixture was evaporated in-vacuo (methanol added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid (185 mg). This material was dissolved once again in methanol (10 mL) and 0.88 ammonia solution (7 mL) was added and the suspension was stirred at 50° C. for 24 hours in a sealed microwave vial. The cooled reaction mixture was evaporated in-vacuo (methanol added to the reaction mixture to reduce foaming during evaporation) to yield a pale yellow solid (186 mg). This crude product was dissolved in the minimum volume of DMSO, applied to a preconditioned reversed-phase Biotage 120 g KP-C18-HS cartridge and eluted using a 5-40% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 15 column volumes (detection wavelength 254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (43 mg).

LCMS (System B): t_(RET)=0.57 min; MH⁺ 789

EXAMPLES Example 1: (1S,6R,8R,9S,10R,15R,17R,18R)-17-(2-amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione ammonium salt

(1S,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-2,4,11,13-tetraoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione (29 mg, 0.032 mmol) was suspended in pyridine (0.5 mL) and the round bottomed flask sealed with a suba seal/nitrogen line inserted. The suspension was heated in an oil bath at 50° C. before simultaneous addition of triethylamine (0.5 mL) and triethylamine trihydrofluoride (0.263 mL, 1.613 mmol) dropwise over 1 minute. The mixture was stirred at 50° C. for 2.5 hours. The solution was allowed to cool to room temperature before addition of HPLC grade acetone (2.8 mL) dropwise over 2 minutes. The resulting very fine suspension was allowed to settle. The majority of the liquid portion was decanted and the slurry was washed successively with acetone (2×2 mL). The resulting wet solid was evaporated to dryness in-vacuo to yield a colourless oil. The material was dissolved in the minimum volume of water, applied to a preconditioned reversed-phase Biotage 60 g KP-C18-HS cartridge and eluted using 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution (3 column volumes) followed by 0-15% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 17 column volumes (detection wavelength 254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (7 mg).

LCMS (System D): t_(RET)=0.18 min; MH⁺ 671

Example 2: (1R,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione, bis ammonium salt

Similarly prepared to Example 1 from (1R,6R,8R,9S,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-2,4,11,13,16-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione (163 mg, 0.181 mmole) giving the title compound as a white solid (81 mg).

LCMS (System D): t_(RET)=0.16 min; MH⁻ 671

Example 3: (1S,6R,8R,9R,10S,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-3,9,12,18-tetrahydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione, bis ammonium salt

Similarly prepared to Example 1 from (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9,18-bis[(tert-butyldimethylsilyl)oxy]-3,12-dihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione (71 mg, 0.079 mmol) giving the title compound as a white solid (23 mg).

LCMS (System D): t_(RET)=0.17 min; MH⁺ 673

Example 4: (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9-fluoro-3,12,18-trihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione, bis ammonium salt

(1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-18-[(tert-butyldimethylsilyl)oxy]-9-fluoro-3,12-dihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione (43 mg, 0.055 mmol) was suspended in pyridine (0.8 mL) and the round bottomed flask sealed with a suba seal/nitrogen line inserted. The suspension was heated in an oil bath at 50° C. before simultaneous addition of triethylamine (1.0 mL) and triethylamine trihydrofluoride (0.44 mL, 2.70 mmol) dropwise over 1 min. The mixture was stirred at 50° C. for 2.5 hours (reaction mixture now a solution). A further 0.2 mL (1.228 mmol) of triethylamine trihydrofluoride was added and the mixture was stirred at 50° C. for 2.5 hours and then at room temperature for 15 hours. HPLC grade acetone (10 mL) dropwise over 2 mins and the resulting very fine suspension was allowed to settle. The majority of the liquid portion was decanted and the resulting wet solid was evaporated to dryness in-vacuo to yield a colourless oil. This material was dissolved in the minimum volume of water, applied to a preconditioned reversed-phase Biotage 60 g KP-C18-HS cartridge and eluted using 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution (3 column volumes) followed by 0-15% acetonitrile (+0.1% 0.88 ammonia solution) in 10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution gradient over 17 column volumes (detection wavelength 254 nm). Appropriate fractions were combined and evaporated in-vacuo to yield the title compound as a white solid (8 mg).

LCMS (System D): t_(RET)=0.17, 0.20 min; MH⁺ 675

The compound was tested in a STING binding assay similar to that described by Li et al (Nature Chemical Biology, 10, 1043-1048, (2014)) and had a pIC₅₀ of >4 

The invention claimed is:
 1. A compound of formula (I)

wherein Y¹ and Y² are independently CH₂ or O; R₁ is OH and R₂ is NH₂ or R¹ is NH₂ and R² is H; R₃ is OH and R₄ is NH₂ or R₃ is NH₂ and R⁴ is H; R₅═OH, or F; R₆═OH, or F; provided at least one of R₅ and R₆ is F, or a tautomer thereof, or a pharmaceutically acceptable salt thereof.
 2. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein at least one of Y₁ and Y₂ is CH₂.
 3. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein Y¹ is CH₂ and Y² is O.
 4. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein Y¹ is O and Y² is CH₂.
 5. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein Y¹ and Y² are both CH₂.
 6. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein Y¹ and Y² are both O and at least one of R₅ and R₆ is F.
 7. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein R³ is NH₂ and R⁴ is H.
 8. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein R² is NH₂ and R¹ is OH.
 9. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein R³ is NH₂, R⁴ is H, R² is NH₂ and R¹ is OH.
 10. A compound or pharmaceutically acceptable salt thereof according to claim 1 wherein R³ is NH₂, R⁴ is H, R² is NH₂, R¹ is OH, R⁵ is OH and R⁶ is OH.
 11. A compound according to claim 1 which is (1S,6R,8R,9R,10R,15R,17R,18R)-17-(2-Amino-6-oxo-6,9-dihydro-1H-purin-9-yl)-8-(6-amino-9H-purin-9-yl)-9-fluoro-3,12,18-trihydroxy-2,4,7,11,13-pentaoxa-3λ⁵,12λ⁵-diphosphatricyclo[13.2.1.0^(6,10)]octadecane-3,12-dione, or a pharmaceutically acceptable salt thereof.
 12. A pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and one or more of pharmaceutically acceptable excipients.
 13. A combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one further therapeutic agent. 